A superconducting rectifier, superconducting diode and methods of manufacture and control thereof

Abstract

The application discloses a superconducting rectifier, a superconducting diode and a manufacturing and control method thereof, and belongs to the technical field of superconducting electronics, and the superconducting rectifier comprises one or more superconducting diodes, the superconducting diode comprises an insulating substrate and a superconducting nanowire, the superconducting nanowire is provided with a narrowed section, the narrowed section is connected with a first gate line and a second gate line, the first gate line and the second gate line are symmetrically arranged and the first gate line and the second gate line are both perpendicular to the superconducting nanowire. The application can realize in-situ reconfigurable inversion symmetry breaking through the nanoscale hot spot controlled by the gate, can realize electrically controllable opening or closing and polarity inversion by adjusting a small gate current, and does not need to change a magnetic field; the superconducting rectifier realizes electrically reconfigurable full-wave and half-wave rectification, and paves the way for the development of scalable and electrically programmable superconducting electronic devices.

Description

Technical Field

[0001] This invention belongs to the field of superconducting electronics technology, specifically relating to a superconducting rectifier, a superconducting diode, and their manufacturing and control methods. Background Technology

[0002] Superconducting electronics, with its inherent advantages of zero resistance, low power consumption, and high speed, is hailed as a highly promising direction for information technology development in the post-Moore's Law era. In many superconducting circuits, especially in superconducting computing and quantum bit readout circuits, the rectifier, as a fundamental nonlinear element, plays a crucial role similar to the "current traffic police" in a traditional semiconductor diode—ensuring that superconducting current can only flow in a single direction, thereby achieving signal rectification, protecting sensitive devices, and constructing logic gates.

[0003] However, since its inception, the technological development of superconducting rectifiers has consistently faced a core bottleneck: the solidification and non-programmability of their functions. Traditional superconducting rectifiers, whether based on asymmetric structures like Josephson junctions (e.g., different junction areas or barrier layers) or utilizing magnetic flux bias to introduce symmetry breaking, have their rectification characteristics (such as polarity, efficiency, and critical current) permanently fixed during the micro / nano fabrication stage. Once manufactured, the device's function cannot be altered. This "hardware as function" paradigm severely limits the flexibility and application range of superconducting circuits.

[0004] As the complexity of superconducting computing systems increases and the demand for reconfigurability and fault tolerance becomes more urgent, rectifiers with fixed functions are no longer sufficient to meet the requirements of advanced architectures. For example, in superconducting processors that require dynamically reconfigurable logic, or in quantum measurement and control systems that need to adaptively adjust the readout path based on the state of qubits, we urgently need to be able to "program" the state of the rectifier in real time using simple electrical signals, enabling it to switch between different modes such as on / off, rectification direction reversal, and full-wave and half-wave rectification. Although some studies in recent years have attempted to control rectification behavior by applying external magnetic fields, these methods often suffer from slow response speeds, low integration density, and the potential for severe electromagnetic interference to surrounding superconducting circuits (especially sensitive qubits).

[0005] Superconducting diodes, devices that allow superconducting current to flow only in a specific direction without energy loss, have become a key component of low-power superconducting electronic devices and quantum technologies. Various strategies have been explored to realize the superconducting diode effect, including artificial superlattices, patterned superconducting thin films, ferromagnetically tunable devices, van der Waals structures, twisted stacks, and chiral superconductors. While some of these systems exhibit significant rectification effects, their switching and polarity control typically rely on external magnetic fields, fundamentally limiting their scalability and the realization of practical circuits.

[0006] For functional superconducting circuits, in-situ electrical tuning of the diode response is extremely important. This tuning capability enables local, rapid, and programmable control within the integrated system, eliminating the need for global magnetic field control. In recent years, gate-controlled superconducting diodes have attracted increasing attention, but most designs are based on Josephson junctions, which require sophisticated fabrication processes and often suffer from limitations in repeatability and scalability. Contactless implementations, such as van der Waals heterostructures, remain rare and typically inefficient. Therefore, a high-performance, easily fabricated superconducting diode that is photolithographically compatible and electrically controllable remains a challenge. Summary of the Invention

[0007] In view of the above-mentioned problems in the prior art, the technical problem to be solved by the present invention is to provide a superconducting rectifier, a superconducting diode and a method for manufacturing and controlling the same, which can realize the function of the superconducting diode through electronic control and is easy to manufacture, and realize a programmable superconducting rectifier.

[0008] Technical Solution: To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A superconducting rectifier includes one or more superconducting diodes. Each superconducting diode includes an insulating substrate and a superconducting nanowire disposed on the insulating substrate. The superconducting nanowire has a narrowing section, and a first gate line and a second gate line are connected to the narrowing section. The first gate line and the second gate line are symmetrically arranged and both the first gate line and the second gate line are perpendicular to the superconducting nanowire. The insulating substrate is a silicon dioxide thin film with a thickness of t1, where 250nm ≤ t1 ≤ 300nm. The superconducting nanowire is a niobium nitride thin film with a thickness of t2, where 8nm ≤ t2 ≤ 12nm. The width of the superconducting nanowire is W1, where 600nm ≤ W1 ≤ 800nm. The width of the narrowing section is W2, where W2 < W1, where 400nm ≤ W2 ≤ 500nm.

[0010] Preferably, the first gate line includes a first hot spot end, and the second gate line includes a second hot spot end. The width of both the first hot spot end and the second hot spot end is W3, where 30nm≤W3≤50nm.

[0011] Preferably, the superconducting rectifier includes four superconducting diodes connected in a bridge configuration.

[0012] The present invention also provides a method for manufacturing a superconducting rectifier, for use in the aforementioned superconducting rectifier, comprising the following steps:

[0013] S1. A niobium nitride layer is magnetron sputtered on an insulating substrate. The thickness of the insulating substrate is t1, 250nm≤t1≤300nm; the thickness of the niobium nitride layer is t2, 8nm≤t2≤12nm.

[0014] S2. A superconducting diode is formed by patterning a niobium nitride layer. The superconducting diode includes a first gate line, a second gate line, and a superconducting nanowire with a narrowed section.

[0015] S3. Pattern the niobium nitride layer to form an enlarged electrode portion on the outer periphery of the superconducting diode and form multiple connection points on the enlarged electrode portion.

[0016] The present invention also provides a superconducting diode control method for controlling the above-mentioned superconducting rectifier, comprising the following steps:

[0017] Step 1: Place the superconducting diode at a temperature of X1K and an external magnetic field of B1Gs;

[0018] Step 2: Apply a DC main current to the superconducting nanowires. The maximum DC main current is 600 μA.

[0019] Step 3: Apply a first operating current to the first gate line. At this time, the superconducting nanowire generates a diode effect, and the superconducting current is unidirectionally conducted, realizing the unidirectional transmission of the superconducting current.

[0020] Step 4: Apply a second operating current to the second gate line, and do not apply current to the first gate line. At this time, the superconducting nanowire generates a diode effect, and the superconducting current is unidirectionally conducted, realizing the unidirectional transmission of the superconducting current. Moreover, the conduction direction is opposite to the conduction direction in Step 3.

[0021] Preferably, 2≤X1≤8, 200≤|B1|≤700, and the first operating current is I. G1 10μA≤|I G1 | ≤20μA, first operating current is I G1 The recapture current Ir is greater than the gate current, and the second operating current is I. G2 10μA≤|I G2 | ≤20μA, the second operating current I G2 It is greater than the gate recapture current Ir.

[0022] The present invention also provides a control method for a superconducting rectifier, for controlling the aforementioned superconducting rectifier, comprising the following steps:

[0023] S10. Place the superconducting rectifier at a temperature of X2K and an external magnetic field of B2Gs; 2≤X2≤8, 200≤|B2|≤700;

[0024] S20. The superconducting rectifier includes four bridge-connected superconducting diodes, namely the first superconducting diode SD1, the second superconducting diode SD2, the third superconducting diode SD3, and the fourth superconducting diode SD4. A first alternating current is applied to the superconducting rectifier, and a second operating current is applied to the second gate line of the four superconducting diodes. All four superconducting diodes are forward diodes, and the superconducting rectifier achieves full-wave rectification.

[0025] S30. Apply a first AC current to the superconducting rectifier, and simultaneously apply a second operating current to the second gate lines of the first superconducting diode SD1 and the fourth superconducting diode SD4. The first superconducting diode SD1 and the fourth superconducting diode SD4 are forward diodes, the gate currents of the second superconducting diode SD2 and the third superconducting diode SD3 are set to zero, and the second superconducting diode SD2 and the third superconducting diode SD3 are in the off state. The superconducting rectifier achieves half-wave rectification.

[0026] The present invention also provides a superconducting diode, including an insulating substrate and a superconducting nanowire disposed on the insulating substrate. The superconducting nanowire has a narrowing section, and a first gate line and a second gate line are connected to the narrowing section. The first gate line and the second gate line are symmetrically arranged.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0028] 1. By setting superconducting nanowires, a first gate line, and a second gate line, in-situ reconfigurable inversion symmetry breaking can be achieved through gate-controlled nanoscale hot spots;

[0029] 2. The electronic control can be turned on or off and the polarity can be reversed by adjusting a small gate current, without changing the magnetic field;

[0030] 3. The compact structure, high efficiency, and flexible electrical control of superconducting diodes pave the way for the development of scalable and electrically programmable superconducting electronic devices, and bring broad prospects for the application of energy-saving logic systems and quantum information systems.

[0031] 4. Simple manufacturing process, compatibility with existing photolithography processes, high performance, and gate control functions provide a scalable platform for programmable superconducting electronic devices and hybrid quantum systems;

[0032] 5. Superconducting rectifiers can independently control the switching on or off of a single superconducting diode and reverse its polarity by adjusting a small gate current without changing the magnetic field. Thanks to the independent control of the superconducting diode, superconducting rectifiers achieve electrically reconfigurable full-wave and half-wave rectification, paving the way for the development of scalable, electrically programmable superconducting electronic devices. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the superconducting diode portion of an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of a partial cross-sectional structure of the superconducting diode in this embodiment;

[0035] Figure 3 This is a schematic diagram of the structure of the superconducting nanowire, the first gate wire, and the second gate wire.

[0036] Figure 4 This is an SEM image of the superconducting diode and a schematic diagram of the measurement wiring in this embodiment;

[0037] Figure 5 This is the measured IV characteristic curve of a superconducting diode at a temperature of 2K and an external magnetic field of -320Gs, with no gate current.

[0038] Figure 6 This is the I-V characteristic curve of a superconducting diode when a 10μA current is applied to the first gate line at a temperature of 2K and an external magnetic field of -320Gs.

[0039] Figure 7 This is the I-V characteristic curve of a superconducting diode when a 10μA current is applied to the second gate line at a temperature of 2K and an external magnetic field of -320Gs.

[0040] Figure 8 The switching curve of the superconducting diode is obtained by applying a 15μA current to the first gate line at a temperature of 2K and an external magnetic field of -320Gs.

[0041] Figure 9 The switching curve of the superconducting diode is obtained by applying a 15μA current to the second gate line at a temperature of 2K and an external magnetic field of -320Gs.

[0042] Figure 10 These are schematic optical microscope images and test wiring diagrams of the superconducting rectifier of this invention.

[0043] Figure 11 This refers to the state of a single superconducting diode in a superconducting rectifier and the corresponding defined diode symbol. Figure 11 Figure a shows the state of a forward-biased diode and its corresponding symbol. Figure 11 Figure b shows the state of the reverse diode and its corresponding symbol. Figure 11 Figure c shows the diode in the off state and its corresponding symbol;

[0044] Figure 12 This is a schematic diagram of the full-wave rectifier circuit of a superconducting rectifier and experimental results. Figure 12Figure a shows the circuit diagram of a superconducting full-wave rectifier. Figure 12 Figure b in the middle shows the test results of the corresponding superconducting full-wave rectifier;

[0045] Figure 13 This is a schematic diagram of the half-wave rectifier circuit of a superconducting rectifier and the experimental results. Figure 13 Figure a shows the circuit diagram of a superconducting half-wave rectifier. Figure 13 Figure b in the middle shows the test results of the corresponding superconducting half-wave rectifier;

[0046] Figure 14 This is a schematic diagram of the structure of the superconducting rectifier of the present invention. Detailed Implementation

[0047] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0048] like Figure 1 and Figure 2As shown, a superconducting diode includes an insulating substrate 1, a superconducting nanowire 2, a first gate line 3, and a second gate line 4. The insulating substrate 1 is made of silicon dioxide thin film and is rectangular in shape. The thickness of the insulating substrate 1 is t1, where 200nm ≤ t1 ≤ 500nm. In this embodiment, t1 = 285nm. The superconducting nanowire 2 is disposed on the insulating substrate 1 and is made of niobium nitride thin film. The superconducting nanowire 2 is rectangular in shape and has a length L1, where 3000nm ≤ L1 ≤ 6000nm. In this embodiment, L1 = 4500nm. The width of the superconducting nanowire 2 is W1, where 600nm ≤ W1 ≤ 800nm. In this embodiment, W1 = 700nm. The thickness of the superconducting nanowire 2 is t2, where 8nm ≤ t2 ≤ 12nm. In this embodiment, t2 = 10nm. The superconducting nanowire 2 has a first end 21 at one end and a second end 22 at the other end. A notch is provided on each side of the middle of the superconducting nanowire 2. In this embodiment, the notch is arc-shaped (it can also be rectangular, triangular, or other shapes). Due to the two notches, the middle portion of the superconducting nanowire 2 forms a narrowing segment 23. The minimum width of the narrowing segment 23 is W2, where W2 < W1, 400nm ≤ W2 ≤ 500nm. In this embodiment, W2 = 500nm. The first gate line 3 and the second gate line 4 are both connected to the narrowing segment 23, and are symmetrically arranged on both sides of the narrowing segment 23. The first gate line 3 and the second gate line 4 are both on the same plane as the superconducting nanowire 2, and are perpendicular to the superconducting nanowire 2. The first gate line 3 includes a first hot spot end 31, which is connected to one side of the narrowing section 23. The first gate line 3 gradually extends outward from the first hot spot end 31 to form an electrode that conducts current to the outside, and the width of the first hot spot end 31 gradually increases outward. The second gate line 4 includes a second hot spot end 41, which is connected to the other side of the narrowing section 23. The second gate line 4 gradually extends outward from the second hot spot end 41 to form an electrode that conducts current to the outside, and the width of the second hot spot end 41 gradually increases outward. The width of the first hot spot end 31 and the second hot spot end 41 is W3, where 30nm≤W3≤50nm. In this embodiment, W3=40nm.

[0049] like Figure 10 , Figure 11 , Figure 12 , Figure 13 and Figure 14 As shown, a superconducting rectifier includes four superconducting diodes as described above. The four superconducting diodes are connected in a bridge configuration to form the superconducting rectifier. The four superconducting diodes are a first superconducting diode SD1, a second superconducting diode SD2, a third superconducting diode SD3, and a fourth superconducting diode SD4. Due to the different positions where the gate current is applied, the superconducting diodes can be either forward-biased or reverse-biased diodes, such as... Figure 11As shown, when a gate current is applied to the second gate line 4, the superconducting diode is a forward diode (e.g., Figure 11 As shown in Figure a), when a gate current is applied to the first gate line 3, the superconducting diode is a reverse diode (as shown in Figure a). Figure 11 As shown in Figure b), when no gate current is applied to either gate line, the corresponding superconducting diode is in the off state (as shown in Figure b). Figure 11 As shown in c), the off state means that the first end 21 and the second end 22 of the superconducting nanowire 2 are in a direct conducting state, without the superconducting diode effect. The state of the superconducting nanowire 2 will change with the change of the current applied to the superconducting nanowire 2 (superconducting state - normal state).

[0050] like Figure 10 , Figure 11 , Figure 12 , Figure 13 and Figure 14 As shown, the first superconducting diode SD1, the second superconducting diode SD2, the third superconducting diode SD3, and the fourth superconducting diode SD4 are connected in a bridge configuration to form a superconducting rectifier. The first superconducting diode SD1 and the third superconducting diode SD3 are connected in series to form the first part, and the second superconducting diode SD2 and the fourth superconducting diode SD4 are connected in series to form the second part. Then, the first part and the second part are connected in parallel to complete the bridge connection. Figure 14 As shown, in this embodiment, the superconducting rectifier includes an insulating substrate 1 and a niobium nitride thin film on the insulating substrate 1. The insulating substrate 1 has a thickness of 285 nm, and the niobium nitride thin film has a thickness of 10 nm. After patterning, the niobium nitride thin film forms four superconducting diodes (i.e., the first superconducting diode SD1, the second superconducting diode SD2, the third superconducting diode SD3, and the fourth superconducting diode SD4) and an enlarged electrode portion located on the outer periphery of the superconducting diodes (e.g., ...). Figure 10 and Figure 14 As shown, Figure 10The center of the red frame represents the superconducting diode, while the other parts are the expanded electrode section. The military green section represents the expanded electrode section, and the black lines represent the patterned exposed silicon dioxide insulating substrate 1. The expanded electrode section expands both ends of the superconducting nanowires 2, and simultaneously expands the outward extension ends of the first gate line 3 and the second gate line 4. After expanding both ends of the four superconducting nanowires 2, the expanded electrode section completes the bridge connection of the four superconducting diodes. The expanded electrode section has a first connection point 201, a second connection point 202, a third connection point 203, a fourth connection point 204, a fifth connection point 205, a sixth connection point 206, a seventh connection point 207, and an eighth connection point 208. The first connection point 201 is connected to the superconducting nanowire of the first superconducting diode SD1. The first end 21 of line 2 corresponds to the second connection point 202, which corresponds to the second end 22 of the superconducting nanowire 2 of the first superconducting diode SD1; the third connection point 203 corresponds to the first end 21 of the superconducting nanowire 2 of the second superconducting diode SD2; the fourth connection point 204 corresponds to the second end 22 of the superconducting nanowire 2 of the second superconducting diode SD2; the fifth connection point 205 corresponds to the first end 21 of the superconducting nanowire 2 of the third superconducting diode SD3; the sixth connection point 206 corresponds to the second end 22 of the superconducting nanowire 2 of the third superconducting diode SD3; the seventh connection point 207 corresponds to the first end 21 of the superconducting nanowire 2 of the fourth superconducting diode SD4; and the eighth connection point 208 corresponds to the first end 21 of the superconducting nanowire 2 of the fourth superconducting diode SD4. The two ends 22 correspond; since the second connection point 202 and the third connection point 203 are located in the same area of ​​the enlarged electrode section, they are connected; the sixth connection point 206 and the seventh connection point 207 are located in the same area of ​​the enlarged electrode section, and they are connected; the first connection point 201 and the fifth connection point 205 are located in the same area of ​​the enlarged electrode section, and they are connected; the fourth connection point 204 and the eighth connection point 208 are located in the same area of ​​the enlarged electrode section, and they are connected; the enlarged electrode section is also provided with a thirty-first connection point 301, a forty-first connection point 401, a thirty-second connection point 302, a forty-second connection point 402, a thirty-third connection point 303, a forty-third connection point 403, a thirty-fourth connection point 304, and a forty-fourth connection point 404. The thirty-first connection point 301 is connected to the first gate line 3 of the first superconducting diode SD1; the forty-first connection point 401 is connected to the second gate line 4 of the first superconducting diode SD1; the thirty-second connection point 302 is connected to the first gate line 3 of the second superconducting diode SD2; the forty-second connection point 402 is connected to the second gate line 4 of the second superconducting diode SD2; the thirty-third connection point 303 is connected to the first gate line 3 of the third superconducting diode SD3; the forty-third connection point 403 is connected to the second gate line 4 of the third superconducting diode SD3; the thirty-fourth connection point 304 is connected to the first gate line 3 of the fourth superconducting diode SD4; and the forty-fourth connection point 404 is connected to the second gate line 4 of the fourth superconducting diode SD4.Multiple connection points are square (or rectangular, circular, or other shapes). In this embodiment, the size of the connection point is 500μm×500μm. Multiple connection points are set to increase the thickness of the niobium nitride film at that location (the niobium nitride film is only 10nm thick, and wire bonding would penetrate the film), which facilitates wire bonding.

[0051] This embodiment also provides a method for manufacturing a superconducting rectifier, which includes the following steps:

[0052] S1. A niobium nitride layer is magnetron sputtered on an insulating substrate 1. The thickness of the niobium nitride layer is t2, where 8nm≤t2≤12nm.

[0053] In this embodiment, the insulating substrate 1 is a silicon dioxide thin film with a length of 7.5 mm, a width of 7.5 mm, a thickness of t1, t1 = 285 nm, and a niobium nitride layer thickness of t2 = 10 nm.

[0054] S2. Four superconducting diodes are formed by patterning the niobium nitride layer. The superconducting diodes include a first gate line 3, a second gate line 4, and a superconducting nanowire 2 with a narrowing segment 23. The patterning includes electron beam exposure and plasma beam etching.

[0055] The specific process of electron beam exposure and plasma beam etching is as follows: Electron beam photoresist (such as a two-layer PMMA (polymethyl methacrylate), with PMMA A2 495 as the bottom layer and PMMA A2 as the second layer) is spin-coated onto the surface of the niobium nitride layer. 950), using electron beam direct writing technology, the designed pattern (the pattern of superconducting nanowire 2, first gate line 3, and second gate line 4; the superconducting nanowire 2 is rectangular with a length of L1 = 4500 nm; the middle part of the superconducting nanowire 2 forms a narrowing segment 23 with a minimum width of W2 = 500 nm; the first hot spot end 31 of the first gate line 3 is connected to the upper middle side of the narrowing segment 23; the first gate line 3 gradually extends outward from the first hot spot end 31, and the width gradually increases outward; the second hot spot end 41 of the second gate line 4 is connected to the lower middle side of the narrowing segment 23; the second gate line 4 gradually extends outward from the second hot spot end 41, and the width gradually increases outward) is exposed on photoresist. After the positive photoresist is developed with MIBK (methyl isobutyl ketone), the exposed area is dissolved, forming a precise nanoscale mask pattern; the sample with the photoresist mask is placed in a plasma etching machine, and the reaction gas (e.g., CHF3 / SF6 = 20:40) is precisely controlled. The formulation and process parameters (e.g., power 80 W, pressure 4.0 Pa) of the sccm (serialized chromatographic matrix) are determined. The active ions in the plasma react chemically with niobium nitride, while simultaneously physical bombardment transfers the pattern from the photoresist to the niobium nitride layer, thus forming four superconducting diodes on the niobium nitride layer. These four superconducting diodes are arranged in two rows. The four superconducting diodes are simultaneously formed on the insulating substrate 1, and are designated as the first superconducting diode SD1, the second superconducting diode SD2, the third superconducting diode SD3, and the fourth superconducting diode SD4.

[0056] S3. The niobium nitride layer is patterned to form an enlarged electrode portion on the outer periphery of the superconducting diode and multiple connection points are formed on the enlarged electrode portion. The four superconducting diodes are connected in a bridge manner through the enlarged electrode portion of the niobium nitride layer to form a superconducting rectifier. The patterning includes ultraviolet lithography and reactive ion etching.

[0057] The specific process is as follows: Photoresist (such as AZ5214 series) is spin-coated onto a niobium nitride thin film and pre-baked (95℃, 2min). Using a mask, the desired pattern (the pattern of the enlarged electrode area) is formed on the photoresist through ultraviolet exposure and development. The sample is placed in a RIE (Reactive Ion Etching) device, and an etching gas (such as CHF3 / SF6 mixed gas) is introduced. Plasma is formed under the excitation of an RF power supply. Through physical bombardment and chemical reaction, the pattern is transferred from the photoresist to the niobium nitride layer, achieving high-precision anisotropic etching. The residual photoresist is removed using a stripping solution or oxygen plasma. The etched sample is then subjected to ultraviolet lithography again for overlay. After secondary lithography and development, the sample is placed in a magnetron sputtering device. Titanium (Ti) layers and gold (Au) layers are sequentially deposited at multiple locations of the enlarged electrode area to form multiple connection points. The connection point size is 500μm×500μm. The titanium layer serves as an adhesion layer with a thickness of 10nm, and the gold layer is used for wire bonding with a thickness of 80nm. The patterned enlarged electrode section expands both ends of the superconducting nanowire 2, as well as the outward extension ends of the first gate line 3 and the second gate line 4. Connection points corresponding to the superconducting diodes are provided on the enlarged electrode section, facilitating wire bonding and enabling the application of main current to both ends of the superconducting nanowire 2, and the application of operating current to the first gate line 3 and the second gate line 4. Four superconducting diodes are bridged together through the enlarged electrode section of the niobium nitride layer to form a superconducting rectifier.

[0058] This embodiment also provides a superconducting diode control method, applied to the aforementioned superconducting diode, comprising the following steps:

[0059] Step 1: Place the superconducting diode at a temperature of X1K and an external magnetic field of B1Gs; 2≤X1≤8, 200≤|B1|≤700.

[0060] In this embodiment, the temperature is 2K and the external magnetic field is -320Gs.

[0061] Step 2: Apply a DC main current to the superconducting nanowire 2. The maximum DC main current is 600μA.

[0062] The specific process is as follows: from 0 to the maximum positive current value (600 μA), then from the maximum positive current value to the maximum negative current value (-600 μA), and then from the maximum negative current value (-600 μA) back to 0, completing one cycle. The superconducting nanowire 2 state: It will change from the superconducting state to the normal state (corresponding to 0 to 600 μA) as the current changes as described above. When the main current exceeds the critical current I of the superconducting nanowire 2... c Time out, I c The specific values ​​are related to the magnetic field / temperature), and then from the normal state to the superconducting state (corresponding to 600 μA to 0, when returning, the main current is less than the recapture current I of the superconducting nanowire 2). rWhen the current returns to the superconducting state, it then returns to the normal state (corresponding to 0 to -600 μA), and then returns to the superconducting state (corresponding to -600 μA to 0), which is one cycle.

[0063] Step 3: Apply a first operating current to the first gate line 3. The first operating current is I. G1 10μA≤|I G1 | ≤20μA, first operating current is I G1 Slightly greater than the gate recapture current Ir, at which point the superconducting nanowire 2 generates a diode effect, and the superconducting current is unidirectionally conducted, realizing the unidirectional transport of the superconducting current;

[0064] In this embodiment, the gate recapture current I r =9.1μA, the first operating current is I G1 =10μA. Due to the application of a small gate current on the first gate line 3, a local nanoscale hot spot is generated at the first hot spot end 31, forming a thermal gradient. This controllably breaks the space inversion symmetry, ultimately generating a non-reciprocal critical current in the superconducting nanowire 2, realizing a nanoscale electrothermal switching superconducting diode. The gate current is slightly larger than the recapture current I. r This is to prevent the entire vertical region near the hot spot in the superconducting nanowire 2 from losing quench (transitioning from the superconducting state to the normal conducting state), thus failing to achieve the effect of the thermal gradient. During the test, the superconducting nanowire 2 was always in a state where a main current was applied: 0→600μA→0→-600μA→0.

[0065] Step 4: Apply a second operating current to the second gate line 4, and do not apply current to the first gate line 3 (the applied current is zero). The second operating current is I. G2 10μA≤|I G2 | ≤20μA, the second operating current is I G2 I G2 Slightly greater than the gate recapture current I r At this point, the superconducting nanowire 2 generates a diode effect, and the superconducting current is unidirectionally conducted, realizing the unidirectional transmission of the superconducting current, and the conduction direction is opposite to the conduction direction in step 3.

[0066] In this embodiment, the gate recapture current I r =9.1μA, the second operating current is I G1=10μA. Due to the application of a small gate current on the second gate line 4 (only one of the first gate line 3 and the second gate line 4 can be selected to apply the working current), a local nanoscale hot spot is generated at the second hot spot end 41, forming a thermal gradient. This controllably breaks the spatial inversion symmetry, and finally generates a non-reciprocal critical current in the superconducting nanowire 2. By controlling the superconducting diode through an electrothermal switch, a nanoscale electrothermal switch type superconducting diode is realized. Furthermore, due to the different positions where the gate current is applied, the polarity of the superconducting diode is also reversed in situ compared to step 3.

[0067] The superconducting diode effect occurs when both spatial and temporal inversion symmetries are broken simultaneously. For example... Figure 3 , Figure 4 As shown, in the device of this embodiment, a nanoscale hot spot is generated in the superconducting nanowire using a gate current, thereby controllably breaking the spatial inversion symmetry and generating a local thermal gradient. Figure 3 As shown, Figure 3 In this context, I+ / V+ represents the positive terminal when applying current and measuring voltage, and I- / V- represents the negative terminal when applying current and measuring voltage. Figure 4 This is a SEM image of the superconducting diode device controlled by the electrothermal switch in this embodiment, with a scale bar of 150 nm. Measurement principle: This device uses the standard four-terminal method for transmission experiments. An input current is applied horizontally across the two ends of the superconducting nanowire 2 (two wires of a Keithley 6221 current source are connected to the two ends of the superconducting nanowire 2), while the output voltage is measured simultaneously (two wires of a Keithley 2182A voltmeter are connected to the two ends of the superconducting nanowire 2). The gate current is input through a vertical line perpendicular to the main channel to one end of the main channel. One wire of the current source (another current source) is connected to either the first gate line 3 or the second gate line 4, and the other wire is connected to one end of the superconducting nanowire 2.

[0068] The controllability of a superconducting diode device controlled by an electrothermal switch leads to an in-situ reversal of polarity. Figure 5 , Figure 6 and Figure 7 The IV characteristic curves are shown with no gate current and with gate currents applied to the upper and lower gates respectively. Figure 5 , Figure 6 and Figure 7 In the graph, the vertical axis represents the voltage output by the superconducting nanowire 2, and the horizontal axis represents the current applied to the superconducting nanowire 2. The voltage is measured by applying current to the superconducting nanowire 2. Figure 5 It means not applying gate current to any gate. Figure 6 It means that current is only applied to the first gate line 3. Figure 7When a current is applied to the second gate line 4, the results show that the device does not exhibit any non-reciprocity when no gate current is applied. However, when a gate current is applied and its magnitude and polarity remain unchanged, the positive and negative critical currents of the device exhibit significant non-reciprocity effects. Furthermore, by changing the position where the gate current is applied, the polarity of the superconducting diode can be reversed in situ.

[0069] The switching characteristics of the superconducting diode in this embodiment are as follows. Figure 8 and Figure 9 As shown, the superconducting state-to-normal state transition and non-reciprocal charge transport related to current polarity in the superconducting diode controlled by the electrothermal switch were tested and studied. Figure 8 and Figure 9 In the diagram, the vertical axis represents the voltage output of the superconducting nanowire 2, and the horizontal axis represents time. First, a square wave current signal is applied to the superconducting nanowire 2, and then the voltage is measured. The difference is: Figure 8 It means that current is only applied to the first gate line 3. Figure 9 By simply applying current to the second gate line 4, the device exhibits obvious switching characteristics. Furthermore, by changing the position of the gate, the polarity switching of the superconducting diode device can be achieved in situ, without changing the magnitude and polarity of the magnetic field and the gate current.

[0070] This embodiment also provides a superconducting rectifier control method, applied to the above-mentioned superconducting rectifier, including the following steps:

[0071] S10. Place the superconducting rectifier at a temperature of X2K and an external magnetic field of B2Gs; 2≤X2≤8, 200≤|B2|≤700.

[0072] In this embodiment, the temperature is 2K and the external magnetic field is 300Gs.

[0073] S20. Apply a first AC current to the superconducting rectifier. The first AC current is a sinusoidal AC current with an amplitude of 700μA and a frequency of 100Hz. The current source is connected to the third connection point 203 and the seventh connection point 207 of the superconducting rectifier. At the same time, apply a second operating current to the second gate line 4 of the first superconducting diode SD1, the second superconducting diode SD2, the third superconducting diode SD3, and the fourth superconducting diode SD4. In this embodiment, the second operating current is 10μA. All four superconducting diodes are forward diodes, and the superconducting rectifier achieves full-wave rectification.

[0074] S30. Apply a first AC current to the superconducting rectifier. The first AC current is a sinusoidal AC current with an amplitude of 700μA and a frequency of 100Hz. The current source is connected to the third connection point 203 and the seventh connection point 207 of the superconducting rectifier. At the same time, apply a second operating current of 10μA to the second gate line 4 of the first superconducting diode SD1 and the fourth superconducting diode SD4. The first superconducting diode SD1 and the fourth superconducting diode SD4 are forward diodes. The gate current of the second superconducting diode SD2 and the third superconducting diode SD3 is set to zero. The second superconducting diode SD2 and the third superconducting diode SD3 are in the off state. The superconducting rectifier achieves half-wave rectification.

[0075] In this embodiment, the superconducting rectifier is tested using the standard four-terminal method for electrical transmission. A sinusoidal alternating current is applied to the superconducting rectifier using a current source. Figure 13 In diagram a, instrument A is a current source, such as... Figure 10 and 14 As shown, one wire of the current source is connected to the third connection point 203, and the other wire is connected to the seventh connection point 207. The current source is a Keithley 6221 AC / DC current source. The output voltage is measured using an oscilloscope. Figure 13 In Figure a, the OSC instrument is an oscilloscope. One wire of the oscilloscope is connected to the fifth connection point 205, and the other wire is connected to the eighth connection point 208. The oscilloscope (OSC) selected is a TBS2000 digital storage oscilloscope. The gate current of each superconducting diode is applied independently through the port corresponding to its first gate line or second gate line.

[0076] like Figure 12 As shown, under conditions of 2K temperature and 300Gs external magnetic field (the superconducting rectifier sample is placed in a three-dimensional superconducting cryogenic magnet system (CMI), with the magnetic field applied perpendicular to the plane of the superconducting rectifier sample), the first superconducting diode SD1, the second superconducting diode SD2, the third superconducting diode SD3, and the fourth superconducting diode SD4 are all configured as forward diodes. A sinusoidal AC drive with an amplitude of 700μA and a frequency of 100Hz is applied to the superconducting rectifier, and a typical full-wave rectified output waveform can be observed (e.g., Figure 12 As shown in Figure b. Figure 12 In graph b, the horizontal axis represents time, and the vertical axis represents the voltage measured by the OSC. Because each superconducting diode possesses direct, local, and reversible electrical control characteristics, by applying a gate current to the gate line on the opposite side, the hot spot position can be moved, thereby reversing the symmetry breaking direction and achieving diode polarity switching. Therefore, the output polarity of the full-wave bridge rectifier can be electrically reconfigured in the field without changing the external magnetic field.

[0077] like Figure 13As shown, this electronic control mechanism supports independent control of each superconducting diode in the superconducting rectifier, which contrasts sharply with the global magnetic field control scheme in the prior art (where all components respond synchronously). Using the same bridge circuit ( Figure 10 Taking a superconducting diode as an example, under the same conditions of 2K temperature and 300Gs external magnetic field, setting the gate current of two of the diodes to zero (the second superconducting diode SD2 and the third superconducting diode SD3 are in the off state) can make them lose their non-reciprocity, while the first superconducting diode SD1 and the fourth superconducting diode SD4 remain forward diodes, thus converting the bridge structure into a half-wave rectifier (by applying a sinusoidal AC drive of 700μA amplitude and 100Hz frequency to the superconducting rectifier, a typical half-wave rectified output waveform can be observed). Figure 13 In graph b, the horizontal axis represents time, and the vertical axis represents the voltage measured by the OSC. The polarity of the half-wave rectifier can also be reversed by adjusting the state of the superconducting diode.

[0078] This embodiment of the superconducting rectifier is composed of four identical superconducting diodes integrated together. Its core working mechanism lies in inducing nanoscale "hot spots" within the superconducting nanowires through gate voltage, dynamically breaking the spatial inversion symmetry of the system, and subsequently triggering a non-reciprocal superconducting-normal state transition originating from an electrothermal switching process, ultimately resulting in non-reciprocal superconducting current transport behavior. This device can flexibly switch between on / off states or reverse rectification polarity in situ by applying a small gate current, thereby supporting independent electrical programming of the rectification function and successfully achieving electrically reconfigurable full-wave and half-wave rectification operations. The design proposed in this invention is compatible with existing photolithography processes, possessing both high performance and flexible gate control capabilities, providing a highly scalable platform for the development of programmable superconducting electronic devices and hybrid quantum systems.

[0079] In summary, the superconducting rectifier of this embodiment can turn the diodes on / off or reverse their polarity in real time through independent electronic control, thus constructing a multifunctional superconducting circuit. This achieves a degree of freedom in electronic control and functional flexibility that was previously unattainable due to limitations imposed by the global magnetic field control architecture.

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A superconducting rectifier, characterized by, The device includes one or more superconducting diodes, each superconducting diode comprising an insulating substrate (1) and a superconducting nanowire (2) disposed on the insulating substrate (1). The superconducting nanowire (2) has a narrowing section (23), on which a first gate line (3) and a second gate line (4) are connected. The first gate line (3) and the second gate line (4) are symmetrically disposed and both the first gate line (3) and the second gate line (4) are perpendicular to the superconducting nanowire (2). The insulating substrate (1) is a silicon dioxide thin film with a thickness of t1, 250nm≤t1≤300nm. The superconducting nanowire (2) is a niobium nitride thin film with a thickness of t2, 8nm≤t2≤12nm. The width of the superconducting nanowire (2) is W1, 600nm≤W1≤800nm. The width of the narrowing section (23) is W2, W2<W1, 400nm≤W2≤500nm.

2. The superconducting rectifier of claim 1, wherein, The first gate line (3) includes a first hot spot end (31), and the second gate line (4) includes a second hot spot end (41). The width of the first hot spot end (31) and the second hot spot end (41) is W3, 30nm≤W3≤50nm.

3. The superconducting rectifier of claim 1, wherein, The superconducting rectifier consists of four superconducting diodes connected in a bridge configuration.

4. A method of manufacturing a superconducting rectifier for manufacturing a superconducting rectifier according to any one of claims 1 to 3, characterized by, Includes the following steps: S1. A niobium nitride layer is magnetron sputtered on an insulating substrate (1). The thickness of the insulating substrate (1) is t1, 250nm≤t1≤300nm; the thickness of the niobium nitride layer is t2, 8nm≤t2≤12nm. S2. A superconducting diode is formed by patterning a niobium nitride layer. The superconducting diode includes a first gate line (3), a second gate line (4), and a superconducting nanowire (2) with a narrowed section (23). S3. Pattern the niobium nitride layer to form an enlarged electrode portion on the outer periphery of the superconducting diode and form multiple connection points on the enlarged electrode portion.

5. A superconducting diode control method for controlling a superconducting rectifier as claimed in any one of claims 1 to 3, characterized by, Includes the following steps: Step 1: Place the superconducting diode at a temperature of X1K and an external magnetic field of B1Gs; Step 2: Apply a DC main current to the superconducting nanowire (2), with a maximum DC main current of 600 μA; Step 3: Apply the first working current to the first gate line (3). At this time, the superconducting nanowire (2) generates a diode effect, and the superconducting current is unidirectionally conducted, realizing the unidirectional transmission of the superconducting current. Step 4: Apply a second working current to the second gate line (4) and do not apply current to the first gate line (3). At this time, the superconducting nanowire (2) generates a diode effect, and the superconducting current is unidirectionally conducted, realizing the unidirectional transmission of the superconducting current. Moreover, the conduction direction is opposite to the conduction direction in step 3.

6. The superconducting diode control method of claim 5, wherein, 2≤X1≤8, 200≤|B1|≤700, the first operating current is I G1 10μA≤|I G1 | ≤20μA, first operating current is I G1 Greater than the gate recapture current I r The second operating current is I G2 10μA≤|I G2 | ≤20μA, the second operating current I G2 Greater than the gate recapture current I r .

7. A control method for a superconducting rectifier, used to control the superconducting rectifier as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S10. Place the superconducting rectifier at a temperature of X2K and an external magnetic field of B2Gs; 2≤X2≤8, 200≤|B2|≤700; S20. The superconducting rectifier includes four bridge-connected superconducting diodes, namely the first superconducting diode SD1, the second superconducting diode SD2, the third superconducting diode SD3 and the fourth superconducting diode SD4. A first AC current is applied to the superconducting rectifier, and a second operating current is applied to the second gate line (4) of the four superconducting diodes. All four superconducting diodes are forward diodes, and the superconducting rectifier achieves full-wave rectification. S30. Apply a first AC current to the superconducting rectifier, and at the same time apply a second operating current to the second gate line (4) of the first superconducting diode SD1 and the fourth superconducting diode SD4. The first superconducting diode SD1 and the fourth superconducting diode SD4 are forward diodes, the gate current of the second superconducting diode SD2 and the third superconducting diode SD3 is set to zero, and the second superconducting diode SD2 and the third superconducting diode SD3 are in the off state. The superconducting rectifier realizes half-wave rectification.

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