High temperature superconducting diode with breakthrough liquid nitrogen temperature and controllable polarity and method of implementation

Abstract

The application discloses a high-temperature superconducting diode with break-through liquid nitrogen temperature and controllable polarity and an implementation method thereof, and belongs to the technical field of semiconductor devices. The application can adapt to different circuit function requirements by presetting a built-in magnetic field to the magnetic substrate and locking the polarity of the high-temperature superconducting diode. The high-temperature superconducting diode is integrated with a single high-temperature superconducting material and a magnetic substrate, and a complex heterojunction is not needed, so that the preparation difficulty and cost are reduced, and large-scale integration is facilitated. The magnetic moment of the magnetic substrate is used as a built-in magnetic field source, so that the dependence on a continuous external magnetic field is completely eliminated, and the convenience and reliability of practical application are improved. A copper oxide high-temperature superconducting sheet is adopted, so that the liquid nitrogen temperature bottleneck is broken through, and the application potential in practical environments is expanded. The application solves the problems of low working temperature and dynamic polarity regulation of the superconducting diode, and has important significance for promoting the development of low-power-consumption electronic circuits and quantum computing as a basic operation element of low-power-consumption high-energy-efficiency circuits.

Description

Technical Field

[0001] This invention relates to semiconductor devices, and more specifically to a high-temperature superconducting diode that breaks through the liquid nitrogen temperature and has controllable polarity, and a method for realizing the same. Background Technology

[0002] A superconducting diode is a device that enables unidirectional superconductivity within a superconductor. Its core characteristic lies in the difference between the forward and reverse superconducting critical currents: when the current amplitude is between the positive and negative critical currents, the current flows in one direction, and the device exhibits zero resistance; however, when the current is reversed, the device exhibits finite resistance. This characteristic gives superconducting diodes the potential to become fundamental computing elements in low-power, high-efficiency logic circuits, and they have potential applications in reducing computational energy consumption and promoting the development of quantum computing.

[0003] The emergence of the superconducting diode effect requires breaking both spatial and temporal inversion symmetries simultaneously. Early research relied heavily on applying external magnetic fields to break temporal inversion symmetry, which significantly limited the practical applications of superconducting diodes. Therefore, research focus gradually shifted to the superconducting diode effect under zero external magnetic field. To date, the superconducting diode effect under zero magnetic field has been observed in several systems, but two key challenges remain: First, the reported operating temperatures of these devices are generally low, mostly still operating within the liquid helium temperature range (4.2 K), severely limiting their application prospects; second, the mainstream methods for breaking spatial inversion symmetry (such as using non-centrosymmetric superconductors or artificially constructing heterojunctions with asymmetric structures) result in superconducting diodes with complex structures, greatly increasing the difficulty of improving their integration density. Furthermore, these methods typically result in the polarity of the superconducting diode being fixed during the fabrication stage, making dynamic adjustment impossible in applications, which greatly limits its flexibility in reconfigurable logic circuits and advanced computing frameworks.

[0004] Therefore, developing a superconducting diode that combines high operating temperature (breaking through the liquid nitrogen temperature of 77 K), true zero-field operation, flexible and adjustable polarity, and simple structure is not only a key breakthrough for realizing the practical application of superconducting diodes, but also a core driving force for promoting the development of low-power electronic circuits. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a high-temperature superconducting diode with controllable polarity that breaks through the liquid nitrogen temperature, and its implementation method, which has the advantages of high operating temperature, zero-field operation, controllable polarity and simple structure.

[0006] One object of the present invention is to provide a high-temperature superconducting diode that breaks through the liquid nitrogen temperature and has controllable polarity.

[0007] The high-temperature superconducting diode of the present invention, which breaks through the liquid nitrogen temperature and has controllable polarity, comprises: a magnetic substrate, current electrodes, a high-temperature superconducting material layer, an asymmetric structure, and a protective layer; wherein, the magnetic substrate is made of an insulating magnetic material that is compatible with the high-temperature superconducting material layer in terms of both lattice and magnetic order temperature, and has a pre-installed built-in magnetic field perpendicular to the surface and with controllable direction; current electrodes are respectively disposed on the magnetic substrate at both ends; a high-temperature superconducting material layer is disposed on the pair of current electrodes, the high-temperature superconducting material layer being a copper oxide high-temperature superconducting sheet having both time-reversal symmetry and spatial-reversal symmetry broken; an asymmetric structure is disposed on the high-temperature superconducting material layer, the asymmetric structure being asymmetrically distributed about the direction of the connection between the pair of current electrodes; and a protective layer is disposed on the high-temperature superconducting material layer;

[0008] A pair of current electrodes are connected to an external power source. During operation, the external power source applies current to the high-temperature superconducting material layer through the pair of current electrodes. The current flows in from one current electrode, passes through the high-temperature superconducting material layer, and then flows out from the other current electrode. When the current flows in one direction, the high-temperature superconducting material layer exhibits zero resistance, i.e., a superconducting state. When the current flows in the opposite direction, it exhibits a finite resistance state, i.e., the high-temperature superconducting material layer exhibits a superconducting diode effect. The built-in magnetic field of the magnetic substrate directly determines and locks the polarity of the superconducting diode effect in the upper high-temperature superconducting material layer through interfacial magnetic exchange and the position of the asymmetric structure.

[0009] Magnetic substrates possess excellent insulation properties to effectively prevent leakage current and ensure stable electrical performance of the high-temperature superconducting diode. In material selection, compatibility with the high-temperature superconducting material layer must be carefully considered: firstly, the two should have high lattice compatibility to ensure effective magnetic exchange interaction at the interface, thereby efficiently controlling superconducting performance; secondly, the magnetic substrate material must possess a magnetic ordering temperature higher than the operating temperature of the high-temperature superconducting diode. The operating temperature of the high-temperature superconducting diode of this invention is higher than the liquid nitrogen temperature (77 K) to ensure the continuous maintenance of a stable ferromagnetic, hypoferromagnetic, weakly ferromagnetic, or antiferromagnetic magnetic ordering state within the operating temperature range of the high-temperature superconducting diode. Magnetic substrates include, but are not limited to, rare-earth positive ferrites. (R=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y), multiferroic Basic oxides ( , , , , , , ), iron garnet ( , , , , , , or spinel ferrite (M = Co, Ni, Mg). An internal magnetic field is established by initial magnetization of the magnetic substrate. This internal magnetic field, through interfacial magnetic exchange, locks the polarity of the superconducting diode effect in the upper high-temperature superconducting material layer. The polarity of the superconducting diode effect is determined by three factors: the direction of the current, the position of the asymmetric structure, and the direction of the internal magnetic field of the magnetic substrate. A pair of current electrodes are connected to the positive and negative terminals of an external power supply, respectively. The positive current direction is defined as flowing from the current electrode connected to the positive terminal to the current electrode connected to the negative terminal, and the negative current direction is the opposite. If the asymmetric structure is located to the left of the positive current direction: when the built-in magnetic field is set, if an external magnetic field perpendicularly upward is applied to the magnetic substrate, the high-temperature superconducting diode is in a superconducting state along the positive current direction and a finite resistance state along the negative current direction; if an external magnetic field perpendicularly downward is applied to the magnetic substrate, the high-temperature superconducting diode is in a finite resistance state along the positive current direction and a superconducting state along the negative current direction. If the asymmetric structure is located to the right of the positive current direction: when the built-in magnetic field is set, if an external magnetic field perpendicularly upward is applied to the magnetic substrate, the high-temperature superconducting diode is in a finite resistance state along the positive current direction and a superconducting state along the negative current direction; if an external magnetic field perpendicularly downward is applied to the magnetic substrate, the high-temperature superconducting diode is in a superconducting state along the positive current direction and a finite resistance state along the negative current direction. By changing the direction of the applied external magnetic field during initialization and controlling the direction of the built-in magnetic field in the magnetic substrate, the polarity of the high-temperature superconducting diode can be non-volatilely "programmed" and reset, thereby achieving specific functions or performance indicators.

[0010] The high-temperature superconducting material layer serves as the carrier for the high-temperature superconducting diode, and the material used is copper oxide high-temperature superconducting material. Compared to conventional superconducting materials, copper oxide superconducting materials have a higher critical temperature, thus enabling the fabrication of high-temperature superconducting diodes that exceed the liquid nitrogen temperature. Copper oxide high-temperature superconducting materials include, but are not limited to, bismuth-based copper oxide superconductors (Bi₂Sr₂Ca). n-1 Cu n O 2n+4+δ ), mercury-based copper oxide superconductors (HgBa2Ca) n-1 Cu n O 2n+2+δ ), copper-based copper oxide superconductors (Cu-1234) or thallium-based copper oxide superconductors (Tl2Ba2Ca) n-1 Cu n O 2n+4 Furthermore, this invention prepares copper oxide high-temperature superconducting material into high-quality thin sheets of the required thickness as high-temperature superconducting material layers, with a thickness of 3~150 nm.

[0011] By fabricating hole structures, sawtooth structures, groove structures, or boss structures on one side of the high-temperature superconducting material layer, an asymmetric structure is formed, making the shape of the high-temperature superconducting material layer asymmetric with respect to the direction of current.

[0012] A pair of current electrodes, made of metal, are connected to the positive and negative terminals of an external power supply, respectively. The positive current flows from the electrode connected to the positive terminal to the electrode connected to the negative terminal, and the negative current flows from the electrode connected to the negative terminal to the electrode connected to the positive terminal. The device further includes one or more pairs of voltage measuring electrodes, located between the current electrodes and placed parallel to them. These voltage measuring electrodes are connected to an external voltage measuring device used to measure the properties of the high-temperature superconducting diode.

[0013] The protective layer uses an insulating material that does not react with the high-temperature superconducting material layer. It tightly encapsulates the core functional layers (high-temperature superconducting material layer / current electrode / magnetic substrate), completely isolating them from the environment. This effectively protects the device from damage or contamination from external environmental factors such as high temperatures and current surges, ensuring the long-term stability and reliability of the device in complex environments. Materials for the protective layer include, but are not limited to, hexagonal boron nitride, amorphous carbon, or diamond-like carbon.

[0014] Another objective of this invention is to propose a method for realizing a high-temperature superconducting diode that breaks through the liquid nitrogen temperature and has controllable polarity.

[0015] The method for realizing a high-temperature superconducting diode with controllable polarity that breaks through the liquid nitrogen temperature according to the present invention includes the following steps:

[0016] 1) Initial magnetization of the magnetic substrate:

[0017] The magnetic substrate is initialized with magnetization to establish a built-in magnetic field, and the polarity of the high-temperature superconducting diode is preset.

[0018] 2) Fabrication of current electrodes:

[0019] Current electrodes are fabricated on a magnetic substrate at both ends;

[0020] 3) Fabrication of high-temperature superconducting material layers:

[0021] High-temperature superconducting copper oxide material is prepared into a high-quality sheet of the required thickness and placed on a magnetic substrate with a pair of current electrodes to obtain a high-temperature superconducting material layer.

[0022] 4) Processing asymmetrical structures:

[0023] Electron resist is spin-coated onto a high-temperature superconducting material layer, and an asymmetric structure is defined and fabricated on one side of the high-temperature superconducting material layer by ion beam etching technology.

[0024] 5) Encapsulation protective layer:

[0025] The protective layer is transferred onto the high-temperature superconducting material layer to obtain a high-temperature superconducting diode;

[0026] 6) Characterization of the superconducting diode effect:

[0027] A pair of current electrodes are connected to an external power source. The external power source applies current to the high-temperature superconducting material layer through the pair of current electrodes. The current flows in from one current electrode, passes through the high-temperature superconducting material layer, and then flows out from the other current electrode. When the current flows in one direction, the high-temperature superconducting material layer exhibits zero resistance, i.e., a superconducting state. When the current flows in the opposite direction, it exhibits a finite resistance state, i.e., the high-temperature superconducting material layer exhibits a superconducting diode effect. The built-in magnetic field of the magnetic substrate directly determines and locks the polarity of the superconducting diode effect in the upper high-temperature superconducting material layer through interfacial magnetic exchange and the position of the asymmetric structure.

[0028] In step 1), the initial magnetization of the magnetic substrate includes the following steps: applying an external magnetic field with an intensity higher than the coercive field of the magnetic substrate along a direction perpendicular to the surface; the magnetic substrate reaches a saturated magnetization state, and then the external magnetic field is removed, thereby giving the magnetized substrate a stable and direction-controllable built-in magnetic field, the direction of which is consistent with the direction of the applied external magnetic field. This built-in magnetic field locks the polarity of the superconducting diode effect in the upper high-temperature superconducting material layer through interfacial magnetic exchange. The polarity of the high-temperature superconducting diode is determined by three factors: the current direction, the position of the asymmetric structure, and the direction of the built-in magnetic field of the magnetic substrate.

[0029] In step 2), current electrodes with a preset pattern are fabricated on a magnetic substrate with a built-in magnetic field by standard micro-nano processes such as spin coating of electron resist, electron beam exposure, development, fixing, electron beam evaporation and resist removal.

[0030] In step 3), a thin sheet is prepared using one or more combined processes of mechanical exfoliation, pulsed laser deposition, epitaxial growth, sputtering deposition, and chemical vapor deposition. Preferably, the high-temperature superconducting material layer is prepared using a combination of tape mechanical exfoliation and low-temperature dry transfer technology: the bulk high-temperature superconducting single crystal is cleaved to obtain a thin sheet, which is then transferred to a preparation substrate at low temperature. The thin sheet on the preparation substrate is then cleaved again and transferred to a transfer medium, and this process is repeated multiple times. The thin sheet obtained from the last cleaving is transferred to a magnetic substrate with current electrodes at a low ambient temperature to obtain the high-temperature superconducting material layer. Specifically, this includes the following steps: i) cleaving the bulk high-temperature superconducting single crystal with tape, and transferring the resulting thin sheet as a primary sample to the preparation substrate; ii) cleaving the primary sample with a transfer medium at an ambient temperature near -80°C, and obtaining a thin sheet as a secondary sample; iii) repeating the above steps once or multiple times; iv) transferring the thin sheet obtained from the last cleaving to a magnetic substrate with current electrodes at an ambient temperature below -30°C to obtain the high-temperature superconducting material layer. The thickness of the primary sample is 200–500 nm, preferably 300–400 nm; the thickness of the secondary sample is 20–300 nm, preferably 20–100 nm; and the thickness of the high-temperature superconducting material layer is 3–150 nm, preferably 3–60 nm. Both the upper and lower surfaces of the high-temperature superconducting material layer are newly cleaved surfaces at low temperatures and will not degrade due to factors such as deoxidation. The transfer medium includes, but is not limited to, polydimethylsiloxane (PDMS). When selecting the type of transfer medium, it is necessary to ensure that the transfer medium has no effect on the high-temperature superconducting material. The entire preparation process is carried out in a glove box (H2O). The process is carried out at 0.1 ppm, with all steps involving high-temperature superconducting materials performed on a cryogenic transfer stage within a glove box. The entire process is water-free and at low temperatures to ensure the high quality of the high-temperature superconducting diode device. This invention employs a "preparing the electrode first, then transferring the sample" process sequence, effectively avoiding the high-temperature damage caused by directly depositing the electrode onto the superconducting material. This helps maintain the intrinsic high performance of the superconducting material, thereby increasing the operating temperature of the high-temperature superconducting diode. Furthermore, the electrode obtained by this method has low contact resistance between the electrode and the transferred high-temperature superconducting material layer, which is beneficial for characterizing the performance of the high-temperature superconducting diode.

[0031] In step 5), i) the bulk protective layer single crystal is cleaved multiple times using tape to obtain a protective layer sample transferred to a transfer medium; ii) at an ambient temperature below -30°C, the protective layer on the transfer medium is transferred to a high-temperature superconducting material layer, so that the structure of the lower layer is completely wrapped by the protective layer; the transfer medium is removed to obtain a high-temperature superconducting diode; the thickness of the protective layer is 3~60 nm, preferably 3~20 nm.

[0032] Advantages of this invention:

[0033] (1) High operating temperature and strong applicability: It has successfully broken through the key bottleneck of liquid nitrogen temperature (77 K), and raised the operating temperature range to the liquid nitrogen temperature range and above. It exhibits excellent and stable operating performance in relatively high temperature working environments, which not only reduces the operating cost of the device, but also greatly expands its applicability potential in practical environments.

[0034] (2) The polarity of the high-temperature superconducting diode is flexibly adjustable: by presetting the magnetization direction of the magnetic substrate and combining it with the position of the asymmetric structure, the polarity of the high-temperature superconducting diode can be locked. This "polarity programming" capability enables the device to adapt to different circuit function requirements.

[0035] (3) Simple structure and easy integration: The core structure of the device is integrated with a single high-temperature superconducting material and a magnetic substrate, without the need to construct a complex heterojunction. This simplified design significantly reduces the difficulty and cost of fabrication and is more conducive to large-scale integration.

[0036] (4) Zero field operation, good practicality: It cleverly utilizes the magnetic moment of the magnetic substrate as a built-in magnetic field source, completely getting rid of the dependence on a continuous external magnetic field, and improving the convenience and reliability of practical applications.

[0037] (5) Built-in protective layer with high stability: The outermost layer of the device integrates a protective layer, which can effectively isolate external environmental factors such as water, oxygen, dust and physical contact from damaging and interfering with the core high-temperature superconducting diode, ensuring its long-term stability and service life under complex working conditions.

[0038] The polarity-tunable high-temperature superconducting diode of this invention has the potential to become a basic computing element for low-power, high-efficiency circuits, which is of great significance for promoting the development of low-power electronic circuits and quantum computing. Attached Figure Description

[0039] Figure 1 The flowchart illustrates the method for fabricating a metal electrode to achieve the electrode of the high-temperature superconducting diode with controllable polarity that breaks through the liquid nitrogen temperature, as described in this invention.

[0040] Figure 2 The flowchart shows the preparation of a high-temperature superconducting material layer, an asymmetric structure, and a protective layer for the method of realizing a high-temperature superconducting diode with controllable polarity that breaks through the liquid nitrogen temperature of the present invention. In this flowchart, (a) to (i) are cross-sectional views of each step.

[0041] Figure 3 This is a schematic diagram of one embodiment of the high-temperature superconducting diode of the present invention, which breaks through the liquid nitrogen temperature and has controllable polarity. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0043] In this embodiment, Bi2Sr2CaCu2O is used. 8+δ (BSCCO) is used as the carrier for high-temperature superconducting diodes; the high-temperature superconducting diodes are manufactured entirely in a glove box (H2O). The high-temperature superconducting diode is prepared in a low-temperature and water-free environment (0.1 ppm) and the electrode is prepared in advance before the diode device is prepared, thus ensuring the quality of the high-temperature superconducting diode.

[0044] The method for realizing a high-temperature superconducting diode that breaks through the liquid nitrogen temperature and has controllable polarity in this embodiment includes the following steps:

[0045] 1) Initial magnetization of the magnetic substrate:

[0046] Y3Fe5O 12 / Gd3Ga5O 12 As a magnetic substrate, an external magnetic field with an intensity higher than the coercive field of the magnetic substrate is applied along a direction perpendicular to the surface; the magnetic substrate reaches a saturation magnetization state, and then the external magnetic field is removed, thereby giving the magnetized substrate a stable and direction-controllable built-in magnetic field, the direction of which is consistent with the direction of the applied external magnetic field; Y3Fe5O 12 As a typical and commonly used ferromagnetic insulator, it has a Curie temperature as high as 560 °C, providing a robust and stable static magnetic field in the operating temperature range of high-temperature superconducting diode devices. Simultaneously, its insulating properties prevent electrical shunting effects with the superconducting phase. The magnetic substrate used in this embodiment is a 0.5 mm thick Gd3Ga5O4 substrate. 12 Epitaxial growth of 3μm thick Y3Fe5O on substrate 12 The composite structure of the thin film has an overall size of 3.5×3.5 mm or 5×5 mm;

[0047] The magnetic substrate was rinsed with isopropanol and then dried with a nitrogen gun to remove any remaining solution from the surface.

[0048] 2) Fabrication of current electrodes:

[0049] like Figure 1 As shown, on a magnetic substrate with a built-in magnetic field, an electron resist was spin-coated at a spin speed of 4500 r / min for 80 s, resulting in a coating thickness of approximately 800 μm. nm; Standard micro-nano processes such as electron beam exposure, development, fixing, electron beam evaporation, and resist removal are used to fabricate metal electrodes with a pre-defined pattern, including a pair of current electrodes and a pair of voltage measurement electrodes. The pair of current electrodes are located at both ends of the magnetic substrate, and the pair of voltage measurement electrodes are located between the pair of current electrodes and placed parallel to the current electrodes. The voltage measurement electrodes are connected to an external voltage measurement device to measure the properties of the high-temperature superconducting diode. The electrodes have a width of 3~5 μm, a length of 70 μm, and a spacing of 4 μm~6 μm between them. The material is titanium / Au, with a titanium layer thickness of 3~7 nm and a gold layer thickness of 10~40 nm.

[0050] The magnetic substrate is immersed in acetone solution for a few minutes to dissolve polymethyl methacrylate (PMMA) until the PMMA layer and the metal layer covering it fall off. Finally, the residual solution on the surface is dried with a nitrogen gun to complete the preparation of the metal electrode.

[0051] 3) Fabrication of high-temperature superconducting material layers:

[0052] i) Place the single-crystal high-temperature superconducting block BSCCO sample on the adhesive surface of a high-efficiency transparent tape (scotch tape), and then cover it with another section of high-efficiency transparent tape to wrap the sample, ensuring that no air bubbles are formed between the sample and the tape to reduce sample breakage during the subsequent peeling process; press the tape lightly with uniform force, then tear the tape to obtain a portion of the BSCCO sample, and then continuously cut new high-efficiency transparent tape and tear it against the tape carrying the thinned sample, repeating this process until a thin layer sample with the required thickness and flatness is obtained. Finally, transfer the large area of ​​BSCCO samples with different thicknesses as primary samples to a silicon (Si) wafer with silicon dioxide (SiO2) deposited on the surface as a preparation substrate.

[0053] ii) Place the preparation substrate with the primary sample on the stage of the transfer stage, and load the glass slide with the first transfer medium PDMS-1 onto the cantilever of the transfer stage, wherein the cantilever is located directly above the stage; in this embodiment, polydimethylsiloxane (PDMS) is used as the transfer medium, but other types of transfer media can be selected as needed, and there is no limitation thereto; the transfer stage is connected to a liquid nitrogen Dewar, and the control switch of the liquid nitrogen delivery system is turned on to introduce liquid nitrogen into the transfer stage to cool the stage and the cantilever; when the temperature of the transfer stage drops to about -80°C, the cantilever is rapidly lowered so that the first transfer medium PDMS-1 on the cantilever adheres to the primary sample, such as Figure 2 As shown in (a); after the primary sample is fully bonded to the first transfer medium PDMS-1, the cantilever is quickly lifted to cleave the primary sample on the substrate onto the first transfer medium PDMS-1, thus obtaining the secondary sample, as shown in (a). Figure 2As shown in (b); at this time, one side of the single crystal sheet is attached to the first transfer medium PDMS-1, and the other side is a new cleavage surface;

[0054] iii) Place the first transfer medium PDMS-1 containing the secondary sample on the stage of the transfer apparatus, and select a new glass slide containing the second transfer medium PDMS-2 and mount it onto the cantilever; similarly, at a temperature of approximately -80°C, rapidly lower the cantilever so that the second transfer medium PDMS-2 on the cantilever adheres to the secondary sample on the first transfer medium PDMS-1, as shown below. Figure 2 As shown in (c); the temperature is approximately -80℃. After the secondary sample and the second transfer medium PDMS-2 are fully bonded, the cantilever is quickly lifted, and the secondary sample is further cleaved using the second transfer medium PDMS-2 to obtain the tertiary sample. The cleaved samples remain on the first and second transfer media PDMS-1 and PDMS-2, respectively, as shown in (c). Figure 2 As shown in (d); at this time, the upper and lower surfaces of the third sample on the second transfer medium PDMS-2 are both surfaces cleaved at low temperature, around -60℃. The pre-prepared Y3Fe5O with metal electrodes is then... 12 / Gd3Ga5O 12 The magnetic substrate is placed on the stage of the transfer stage apparatus, and the second transfer medium PDMS-2 with the tertiary sample on the cantilever remains unchanged, as follows. Figure 2 As shown in (e); the temperature is approximately -30℃. The relative positions of the thin film and the metal electrode are observed using a microscope. The displacement function of the transfer stage is used to move the tertiary sample directly above the metal electrode, thus obtaining the high-temperature superconducting material layer, as shown. Figure 2 As shown in (f);

[0055] 4) Processing asymmetrical structures:

[0056] A suitable electronic resist was spin-coated onto the high-temperature superconducting material layer. This electronic resist serves to protect the core functional layers of the high-temperature superconducting diode (high-temperature superconducting material layer / current electrode / magnetic substrate) to reduce the degradation of the superconducting properties of the BSCCO thin film during subsequent micro / nano fabrication. In this embodiment, polymethyl methacrylate (PMMA) was used, with a spin-coating speed of 4500 r / min, a spin-coating time of 80 s, and a spin-coating thickness of approximately 800 μm. nm, other types of protection can also be selected as needed, and there are no restrictions on this;

[0057] By designing a pattern of single-sided hole arrays and performing ion beam etching on a high-temperature superconducting material layer, an edge-asymmetric structure is obtained, such as... Figure 2 As shown in (g);

[0058] 5) Encapsulation protective layer:

[0059] The temperature of the transfer stage was adjusted to -80 ℃. Hexagonal boron nitride (hBN) was selected as the protective layer, and the material was cleaved into a thin sample of suitable thickness and smooth surface by peeling off adhesive tape. Then, at a temperature of about -60 ℃, a glass slide with a third transfer medium PDMS-3 was selected, and the adhesive tape with the protective layer was pressed onto the clean third transfer medium PDMS-3. The tape was then gently peeled off, thus obtaining a large-area protective layer on the third transfer medium PDMS-3.

[0060] A glass slide with a protective layer and a third transfer medium PDMS-3 is mounted on a cantilever, while keeping the core functional layer of the high-temperature superconducting diode on the stage unchanged. The relative positions of the protective layer and the core functional layer of the high-temperature superconducting diode are observed through a microscope, and the displacement function of the transfer stage is used to move the protective layer to directly above the core functional layer of the high-temperature superconducting diode.

[0061] Once the transfer stage is heated to -60°C, the cantilever is slowly lowered to ensure close contact between the protective layer on the PDMS-3 and the core functional layer of the high-temperature superconducting diode on the magnetic substrate. Figure 2 As shown in (h); continue heating to -30 ℃, slowly raise the cantilever to separate the third transfer medium PDMS-3 from the protective layer, as shown. Figure 2 As shown in (i); at this time, the core functional layer of the high-temperature superconducting diode is fully wrapped by the protective layer, which can effectively avoid damage or pollution from the external environment and ensure the high quality of the high-temperature superconducting diode.

[0062] 6) Characterization of superconducting diode effect:

[0063] A pair of current electrodes are connected to an external power source, which applies current to the high-temperature superconducting material layer through these electrodes. The current flows in from one electrode, passes through the layer, and exits from the other. A pair of voltage measuring electrodes are connected to an external voltage measuring device to measure the properties of the superconducting diode: when the current flows in one direction, the high-temperature superconducting material layer exhibits zero resistance (superconducting state), while when the current flows in the opposite direction, it exhibits finite resistance (superconducting diode effect). The built-in magnetic field of the magnetic substrate, through interfacial magnetic exchange and the position of the asymmetric structure, directly determines and locks the polarity of the superconducting diode effect in the upper high-temperature superconducting material layer.

[0064] A pair of current electrodes are connected to the positive and negative terminals of an external power supply, respectively. The positive current direction is defined as flowing from the current electrode connected to the positive terminal to the current electrode connected to the negative terminal, and the negative current direction is the opposite. If the asymmetric structure is located to the left of the positive current direction: when the built-in magnetic field is set, if an external magnetic field perpendicularly upward is applied to the magnetic substrate, the high-temperature superconducting diode is in a superconducting state along the positive current direction and a finite resistance state along the negative current direction; if an external magnetic field perpendicularly downward is applied to the magnetic substrate, the high-temperature superconducting diode is in a finite resistance state along the positive current direction and a superconducting state along the negative current direction. If the asymmetric structure is located to the right of the positive current direction: when the built-in magnetic field is set, if an external magnetic field perpendicularly upward is applied to the magnetic substrate, the high-temperature superconducting diode is in a finite resistance state along the positive current direction and a superconducting state along the negative current direction; if an external magnetic field perpendicularly downward is applied to the magnetic substrate, the high-temperature superconducting diode is in a superconducting state along the positive current direction and a finite resistance state along the negative current direction.

[0065] like Figure 3 As shown, the high-temperature superconducting diode of this embodiment includes: a magnetic substrate, a pair of current electrodes, a pair of voltage measuring electrodes, a high-temperature superconducting material layer, an asymmetric structure, and a protective layer; wherein, on the surface of the magnetic substrate, the pair of current electrodes are located at both ends of the magnetic substrate, and the pair of voltage measuring electrodes are located between the pair of current electrodes and placed parallel to the current electrodes; a high-temperature superconducting material layer is disposed on the pair of current electrodes and the pair of voltage measuring electrodes; an asymmetric structure is disposed on the high-temperature superconducting material layer, the asymmetric structure being asymmetrically distributed about the direction of the connection between the pair of current electrodes, such that the high-temperature superconducting material layer forms a spatial inversion symmetry broken about the direction of the connection between the pair of current electrodes; a protective layer is disposed on the high-temperature superconducting material layer.

[0066] The high-temperature superconducting diode obtained in this embodiment has at least the following technical effects: its operating temperature can exceed the liquid nitrogen temperature (77 K), and it has a wide operating temperature range; by pre-treating the magnetic substrate and controlling the direction of the applied magnetic field, the polarity of the high-temperature superconducting diode can be flexibly adjusted; the high-temperature superconducting diode effect can be achieved under zero applied magnetic field; the high-temperature superconducting diode has a simple structure and is easy to process.

[0067] Finally, it should be noted that the purpose of disclosing the embodiments is to help further understand the present invention. However, those skilled in the art will understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the scope of protection of the present invention is defined by the claims.

Claims

1. A high-temperature superconducting diode with temperature exceeding that of liquid nitrogen and controllable polarity, characterized in that, The high-temperature superconducting diode comprises: a magnetic substrate, current electrodes, a high-temperature superconducting material layer, an asymmetric structure, and a protective layer; wherein, the magnetic substrate is made of an insulating magnetic material that is compatible with the high-temperature superconducting material layer in terms of both lattice and magnetic order temperature, and has a pre-installed built-in magnetic field perpendicular to the surface and with controllable direction; current electrodes are respectively disposed on the magnetic substrate at both ends; a high-temperature superconducting material layer is disposed on the pair of current electrodes, the high-temperature superconducting material layer being a copper oxide high-temperature superconducting sheet; an asymmetric structure is disposed on the high-temperature superconducting material layer, the asymmetric structure being asymmetrically distributed about the direction of the connection between the pair of current electrodes; and a protective layer is disposed on the high-temperature superconducting material layer; An external power source applies current to the high-temperature superconducting material layer through a pair of current electrodes. The current passes through the high-temperature superconducting material layer, which exhibits a superconducting diode effect: when the current flows in one direction, the high-temperature superconducting material layer exhibits zero resistance characteristics, and when the current flows in the opposite direction, it exhibits a finite resistance state. The built-in magnetic field of the magnetic substrate determines the polarity of the superconducting diode effect in the high-temperature superconducting material layer through interfacial magnetic exchange and the position of the asymmetric structure.

2. The high-temperature superconducting diode according to claim 1, characterized in that, The magnetic substrate is made of rare-earth ferrite or multiferroic material. Basic oxides, iron garnets, or spinel ferrites.

3. The high-temperature superconducting diode according to claim 1, characterized in that, The high-temperature superconducting material layer adopts bismuth-based copper oxide superconductor, mercury-based copper oxide superconductor, copper-based copper oxide superconductor or thallium-based copper oxide superconductor, and the thickness of the high-temperature superconducting material layer is 3~150nm.

4. The high-temperature superconducting diode according to claim 1, characterized in that, The asymmetric structure is a hole structure, sawtooth structure, groove structure or boss structure processed on one side of a high-temperature superconducting material layer.

5. The high-temperature superconducting diode according to claim 1, characterized in that, The protective layer is made of hexagonal boron nitride, amorphous carbon, or diamond-like carbon.

6. A method for realizing a high-temperature superconducting diode with controllable polarity that breaks through the liquid nitrogen temperature according to claim 1, characterized in that, The implementation method includes the following steps: 1) Initial magnetization of the magnetic substrate: Initial magnetization of the magnetic substrate to establish a built-in magnetic field; 2) Fabrication of current electrodes: Current electrodes are fabricated on a magnetic substrate at both ends; 3) Fabrication of high-temperature superconducting material layers: A copper oxide high-temperature superconducting material is prepared into a thin sheet of the required thickness and placed on a magnetic substrate with a pair of current electrodes to obtain a high-temperature superconducting material layer. 4) Processing asymmetrical structures: Asymmetric structures were defined and fabricated on one side of a high-temperature superconducting material layer; 5) Encapsulation protective layer: The protective layer is transferred onto the high-temperature superconducting material layer to obtain a high-temperature superconducting diode; 6) Characterization of superconducting diode effect: An external power source applies current to the high-temperature superconducting material layer through a pair of current electrodes. The current passes through the high-temperature superconducting material layer, which exhibits a superconducting diode effect: when the current flows in one direction, the high-temperature superconducting material layer exhibits zero resistance characteristics, i.e., a superconducting state; when the current flows in the opposite direction, it exhibits a finite resistance state. The built-in magnetic field of the magnetic substrate determines the polarity of the superconducting diode effect in the high-temperature superconducting material layer through interfacial magnetic exchange and the position of the asymmetric structure.

7. The implementation method according to claim 6, characterized in that, In step 1), the initial magnetization of the magnetic substrate includes the following steps: An external magnetic field with a strength higher than the coercive field of the magnetic substrate is applied along a direction perpendicular to the surface; the magnetic substrate reaches a saturated magnetization state, and then the external magnetic field is removed, so that the magnetized substrate has a stable and direction-controllable built-in magnetic field, the direction of which is consistent with the direction of the applied external magnetic field.

8. The implementation method according to claim 6, characterized in that, In step 2), a current electrode is fabricated on a magnetic substrate with a pre-installed built-in magnetic field by a micro-nano process of spin coating electron resist, electron beam exposure, development, fixing, electron beam evaporation and resist removal.

9. The implementation method according to claim 6, characterized in that, In step 3), the high-temperature superconducting material layer is prepared by mechanical exfoliation, pulsed laser deposition, epitaxial growth, sputtering deposition or chemical vapor deposition, and the thickness of the high-temperature superconducting material layer is 3~150nm.

10. The implementation method according to claim 6, characterized in that, In step 6), the polarity of the superconducting diode effect is determined by three factors: the current direction, the position of the asymmetric structure, and the direction of the built-in magnetic field of the magnetic substrate. A pair of current electrodes are connected to the positive and negative terminals of an external power source, respectively. The positive current direction is defined as the flow from the current electrode connected to the positive terminal to the current electrode connected to the negative terminal, and the negative current direction is the flow from the current electrode connected to the negative terminal to the current electrode connected to the positive terminal. For the asymmetric structure located on the left edge along the positive current direction: when setting the built-in magnetic field, applying a vertically upward external magnetic field to the magnetic substrate will cause the high-temperature superconducting diode to move along the positive current direction. When the built-in magnetic field is applied to the magnetic substrate, the high-temperature superconducting diode is in a superconducting state along the positive current direction and a finite resistance state along the negative current direction. When an external magnetic field is applied vertically downward to the magnetic substrate, the high-temperature superconducting diode is in a finite resistance state along the positive current direction and a superconducting state along the negative current direction. When an external magnetic field is applied vertically downward to the magnetic substrate, the high-temperature superconducting diode is in a superconducting state along the positive current direction and a finite resistance state along the negative current direction.

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