A superconducting diode device based on embedding double quantum dots in a ring structure

Abstract

This invention provides a device based on a double quantum dot superconducting diode embedded in a ring structure. This quantum dot structure successfully combines the superconducting diode effect, spin-orbit coupling effect, and gate modulation to achieve unidirectional current and precise control of quantum states. The device modulates the electron coupling strength and transport characteristics between quantum dots by adjusting the phase of the two superconducting electrodes, the material composition and length of the tunnel junction, the external magnetic field, and the gate voltage. It is suitable for applications in superconducting electronic devices, quantum computing, and quantum information processing.

Description

Technical Field

[0001] This invention relates to the field of superconducting electronic device technology, and in particular, to a device based on a superconducting diode with two quantum dots embedded in a ring structure. Background Technology

[0002] With the rapid development of quantum computing and superconducting electronics, especially the research on quantum dot systems, research has gradually become a focus of attention. This research has not only promoted the development of fundamental physics but also provided entirely new design ideas for future quantum information processing devices. In superconducting quantum dot systems, phenomena such as the Josephson effect, spin-orbit interaction, the existence of Majorana quasiparticles, and their manipulation have been extensively studied. These phenomena enable precise manipulation of quantum states, providing a foundation for high-performance quantum computing and the design of topological qubits.

[0003] Existing quantum dot-superconducting device designs are typically limited by several factors. First, the Coulomb blockade effect effectively impedes the free flow of electrons, but achieving precise Coulomb control within quantum dots remains a complex challenge. Second, while spin-orbit interactions can break time-reversal symmetry and thus control quantum states, further optimization is needed when dealing with complex topological superconducting devices, specifically how to precisely adjust physical quantities such as applied magnetic fields and gate voltages.

[0004] Currently, most research in the industry focuses on achieving limited control through simple quantum dot-superconducting structures. However, given the complex demands of real-world applications, this single-effect control method is clearly insufficient to meet the requirements of future quantum computing and superconducting device development. Existing devices still have significant shortcomings in terms of quantum state stability, control precision, and system integration, particularly in the limited utilization of the synergistic effects of multiple physical effects, making it difficult to achieve comprehensive control of the topological superconducting state.

[0005] Therefore, how to more closely integrate quantum dots with superconductors, especially through the synergistic modulation of external magnetic fields, spin-orbit interactions, and gate voltage to achieve high-precision control of quantum states and electron transport paths, has become a key problem urgently needing to be solved in the fields of quantum electronics and superconducting devices. This patent proposes a tunable electronic device based on embedding two quantum dots in a ring structure and the superconducting effect. It can effectively utilize the above three modulation methods to achieve precise control of electronic behavior and quantum states, providing a novel design approach for the development of superconducting devices and quantum computing. Summary of the Invention

[0006] This invention proposes a superconducting diode device based on a ring structure embedded with two quantum dots. It aims to provide a novel design scheme suitable for superconducting devices by synergistically controlling quantum interference effects, gate voltage, spin-orbit interaction, and applied magnetic field. This design can effectively achieve high-precision control of quantum states and electron transport paths, providing a solid foundation for future research in quantum computing, topological superconductivity, and related applications.

[0007] To achieve the above objectives, this invention proposes a device based on a superconducting diode with two quantum dots embedded in a ring structure, the device comprising: Semiconductor substrate silicon 100; A semiconductor tunnel junction 400, wherein the tunnel junction is composed of a first tunnel junction 401 and a second tunnel junction 402, which are arranged in a ring structure; Superconductor 300, the first superconductor 301 and the second superconductor 302 are interconnected through the first tunnel junction 401 and the second tunnel junction 402 and are placed on the semiconductor substrate silicon 100, the first superconductor 301 is the source electrode and the second superconductor 302 is the drain electrode; Quantum dot 200, wherein the quantum dot 200 is embedded in the second tunnel junction 402 to form a series structure; The device applies a magnetic flux of 500 in the annular structure. The vertical magnetic field.

[0008] The coupling strength between the first quantum dot 201 and the first superconductor 301 is The coupling strength between the second quantum dot 202 and the second superconductor 302 is .

[0009] The first quantum dot 201 and the second quantum dot 202 are respectively connected to an external gate 600 for energy level modulation.

[0010] The first quantum dot 201 and the second quantum dot 202 are either spin quantum dots or InAs quantum dots.

[0011] The first superconductor 301 and the second superconductor 302 are made of superconducting materials with high critical temperatures or materials with strong spin-orbit coupling.

[0012] Optionally, the operating state of the quantum dots can be changed by altering the operating temperature.

[0013] Optionally, the ring-shaped superconducting structure can be deformed or extended according to different application scenarios, adjusting the radius, thickness, or shape of the rings. For example, it can be designed as a multi-ring structure to improve the coupling effect, or different connection methods can be used to achieve more complex electron transport paths.

[0014] Optionally, it can be integrated with other quantum devices, such as quantum computing units, quantum memories, or spintronic devices.

[0015] Optionally, different control algorithms and strategies can be selected based on the actual application, such as machine learning-based intelligent control, traditional feedback control, or dynamic optimization algorithms.

[0016] In summary, this invention, through a ring-shaped superconducting structure embedded with two quantum dots and combined with the manipulation of various physical effects, solves the bottleneck problems of existing quantum dot-superconducting systems in terms of Josephson current, quantum state manipulation precision, and system stability. This invention not only possesses significant theoretical innovation but also has strong practical application value, particularly in the design and development of superconducting electronic devices, superconducting quantum computing, and related fields.

[0017] The present invention has the following beneficial effects: 1. Improved precision and flexibility of quantum state manipulation: This invention achieves high-precision manipulation of quantum states by embedding two quantum dots in a ring-shaped superconducting structure and combining quantum interference effects, spin-orbit interactions, and external magnetic fields. The embedding design of the two quantum dots makes the electron transport path more controllable, thereby improving the system's adjustment precision and flexibility, making it particularly suitable for complex quantum information processing and topological quantum computing.

[0018] 2. Enhanced system tunability and versatility: By introducing an external magnetic field and gate voltage, this invention dynamically controls the electron transport phase, path, and quantum state, forming a multi-effect synergistic control quantum device design that can adapt to the quantum state switching requirements under different operating environments. Compared to traditional quantum devices, this invention offers greater design flexibility and can be widely applied in various quantum computing and quantum communication devices.

[0019] 3. Achieving Diode Effect of Josephson Current and Effective Control of Superconducting State: The structural design in this invention breaks time-reversal symmetry by controlling the interaction between the magnetic field and spin-orbit, resulting in a diode effect of Josephson current and the formation of a topologically protected quantum state. Topological superconducting state and its related effects are crucial for quantum computing devices, and this invention provides a solid foundation for such devices.

[0020] 4. Enhanced device anti-interference capability and system stability: The dual-quantum-dot structural design, combined with external control methods, effectively suppresses external noise interference, significantly improving system stability and reliability. In topological quantum computing and quantum communication, this invention can effectively reduce quantum state decoherence, ensuring the accuracy and continuity of data transmission and processing.

[0021] 5. Simplified fabrication and operation of quantum devices: The dual-quantum-dot embedded ring superconducting structure design employed in this invention is characterized by its simple structure and ease of implementation, which can reduce the manufacturing cost and complexity of quantum devices. Simultaneously, the flexible controllability of the applied field and gate makes device operation more convenient, suitable for large-scale integration and industrial applications.

[0022] 6. Broad Application Prospects: This invention is not only applicable to the design of superconducting electronic devices, but also to triplet superconductivity, quantum computing, quantum information processing, and spintronics. Its superior tunability and stability endow quantum technology with a wider range of application possibilities, meeting the needs of future quantum computing and communication devices. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 Specific structural diagrams provided for examples of the present invention; Legend: 100. Semiconductor substrate; 200. Quantum dot structure; 201. Semiconductor quantum dot 1; 202. Semiconductor quantum dot 2; 300. Superconductor structure; 301. Superconductor source electrode; 302. Superconductor drain electrode; 400. Tunnel junction superconducting ring structure; 401. Tunnel junction between left and right superconductors; 402. Tunnel junction between left and right superconductors embedded with dual quantum dots; 500. Magnetic flux for structural control; 600. Gate for structural control; 601. Gate for controlling a first semiconductor quantum dot; 602. Gate for controlling a second semiconductor quantum dot. Detailed Implementation

[0024] To make the above-mentioned objects, features, and advantages of the present invention more readily understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In addition to the following detailed description, the present invention can also be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] A device based on a superconducting diode with two quantum dots embedded in a ring structure is disclosed, comprising: The two superconductors 300 interact directly through a semiconductor tunnel junction 400, with an interaction strength of [value missing]. On the other hand, it is connected to two semiconductor quantum dots 200 through a tunnel junction 402, forming a dual-channel structure for electron transport. A vertical magnetic field applied to the system generates a magnetic flux 500, which has a coupling strength... This causes a phase The coupling strengths between the two quantum dots 200 and the superconductor 300 are respectively and Due to the spin-orbit coupling interaction in quantum dot 200, the coupling strength between quantum dot 200 and superconductor 300 exhibits characteristics related to electron spin. Relevant phases and Two quantum dots 200 interact through a tunnel junction 402 with a strength of [value missing]. The energy levels in quantum dot 200 are modulated by an external gate voltage 600. Example

[0026] The specific implementation method is as follows: The coupling strength of the superconducting tunnel 400 in the control structure is The coupling strengths between the two quantum dots 200 and the superconductor 300 are respectively and At this time, the device is connected to a gate voltage of 600Vgs.

[0027] When the phases of the two superconductors 300 are different, a Coulomb pyramid structure will appear in the system, and the conductivity of the quantum dot 200 will be hindered.

[0028] In practical operation, under a certain superconductor phase difference of 300, by adjusting the voltage of the gate 600, the energy level of the quantum dot 200 can be aligned with the Fermi level of the external electrode, thereby breaking the Coulomb blockade, allowing electron tunneling, precisely controlling the number of electrons in each quantum dot, forming a stable Coulomb peak, and thus achieving regulation of Josephson current transmission.

[0029] Using this method, the Josephson current can be stably controlled at lower temperatures, avoiding the influence of stray charges and achieving precise control of current flow in the superconducting ring structure.

[0030] Example The specific implementation method is as follows: The coupling strength of the quantum dot tunnel 402 in the control structure is The coupling strengths between the two quantum dots 200 and the superconductor 300 are respectively and At this time, the quantum dot 200 in the device is selected as InAs quantum dot.

[0031] In tunnel junction superconducting ring structures, due to the strong spin-orbit interaction, the spin and orbital motion of electrons are coupled, thereby breaking the time reversal symmetry.

[0032] During operation, the intensity of spin-orbit interaction is changed by adjusting the voltage of the gate 600 or introducing an electric field, thereby controlling the direction of electron motion and spin state, controlling the transition between spin states, and thus affecting the motion path of electrons in the quantum dot. Example

[0033] The specific implementation method is as follows: The coupling strength of the quantum dot tunnel 402 in the control structure is The coupling strengths between the two quantum dots 200 and the superconductor 300 are respectively and At this time, a magnetic field B is applied externally to the device, causing a magnetic flux of 500 Ω to appear in the annular structure of the device. .

[0034] In the tunnel junction superconducting ring structure, an external magnetic field perpendicular to the semiconductor substrate 100 is applied to make the magnetic flux 500 pass through the center of the ring.

[0035] By adjusting the magnitude of the magnetic flux 500, the electron transport path and phase distribution in the system can be precisely controlled. This modulation method is suitable for designing quantum interference devices, enabling precise switching control of current and producing a superconducting diode effect.

[0036] In operation, the conductivity of the dual quantum dot 200 system is affected by changing the strength of the applied external magnetic field. For example, changing the magnetic flux 500 causes the conductivity to oscillate (i.e., Aharonov-Bohm oscillation), thereby achieving precise control over the tunneling rate of the quantum dot 200.

[0037] In addition, the external magnetic field breaks the time reversal symmetry, causing the system to enter the topological superconducting state, which is crucial for realizing Majorana edge states and their application in topological quantum computing.

[0038] This dual-quantum-dot 200 system exhibits quantum interference phenomena through precise control via a gate voltage of 600, the coupling effect between quantum dots 200, and an applied magnetic field. The magnitude and direction of the Josephson current can be adjusted by changing the gate voltage of 600. Furthermore, by breaking the time-reversal symmetry through spin-orbit interaction, a superconducting diode effect is achieved, making the direction of the Josephson current in the system adjustable.

[0039] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A device based on a superconducting diode with two quantum dots embedded in a ring structure, characterized in that, include: Semiconductor substrate silicon 100; Semiconductor tunnel junction 400; The first superconductor 301 and the second superconductor 302 are interconnected through the first tunnel junction 401 and the second tunnel junction 402, and are placed on the semiconductor substrate silicon 100; The first tunnel junction 401 and the second tunnel junction 402 are in the form of a ring structure; The first superconductor 301 is the source electrode, and the second superconductor 302 is the drain electrode; the first quantum dot 201 and the second quantum dot 202 are embedded in the second tunnel junction.

2. The apparatus according to claim 1, characterized in that, The coupling strength between the first quantum dot 201 and the first superconductor 301 is The coupling strength between the second quantum dot 202 and the second superconductor 302 is .

3. The apparatus according to claim 2, characterized in that, Applying a magnetic flux of 500 to the ring structure A vertical magnetic field is present in the device.

4. The apparatus according to claim 3, characterized in that, The first quantum dot 201 and the second quantum dot 202 are respectively connected to external gates for energy level modulation.

5. The apparatus according to claim 4, characterized in that, The first quantum dot 201 and the second quantum dot 202 are either spin quantum dots or InAs quantum dots.

6. The apparatus according to claim 4, characterized in that, The first superconductor 301 and the second superconductor 302 are made of superconducting materials with high critical temperatures or materials with strong spin-orbit coupling.

7. The apparatus according to claims 1-6, characterized in that, The superconducting diode effect is achieved by changing the period of the Josephson current.

8. The apparatus according to claims 1-6, characterized in that, The device is applied in the fields of superconducting diode electronic devices, quantum computing, or superconducting quantum information processing.

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