A spin-momentum locking regulation device with topological chern number real-time monitoring and automatic calibration and a control method thereof

Abstract

The application discloses a spin-momentum locking regulation and control device with real-time topological Chern number monitoring and automatic calibration and a control method thereof. According to a projection geometry axiom system, a topological Chern number is a homotopy invariant of a fiber bundle, and a non-zero Chern number indicates that a system is in a topologically nontrivial phase, and provides topological protection for spin-momentum locking. The device comprises a topological insulator core layer (with a non-zero topological Chern number and a spin-momentum locking surface state), a gate regulation electrode, a topological Chern number monitoring module (real-time monitoring through non-local transport measurement or Berry curvature measurement), a topological Chern number deviation judgment module (calculating ) and an automatic calibration module (automatically adjusting a gate voltage according to ). When deviating from a target integer value, the system automatically calibrates to lock back to the non-zero integer value, and maintains the integrity of the topological protection of the spin-momentum locking. The application realizes real-time monitoring and automatic calibration of the topological Chern number, eliminates a topological decoherence channel, and is suitable for topological quantum bit control, spin electronics devices and quantum information processing scenes.

Description

Technical Field

[0001] This invention relates to the fields of topological electronics, spintronics, and quantum information devices, specifically to a spin-momentum locking control device and its control method for real-time monitoring and automatic calibration of the topological Chern number. This invention can be applied to topological qubit manipulation, spintronic devices, quantum information processing, and topological quantum computing, and is particularly suitable for applications requiring real-time monitoring of the topological Chern number. It also automatically calibrates spin-momentum locking parameters to maintain topology protection for quantum device applications. Background Technology

[0002] According to the axioms of projective geometry, a physical system is defined as a high-dimensional fiber bundle. In the base manifold The projected section on the surface is determined by the projection weight. Fully characterized. Topological Chern number. Defined as the Berry curvature integral of the fiber bundle over the Brillouin zone: Topological Chern number Takes integer values, non-zero Chern numbers This indicates that the system is in a topologically nontrivial phase. In the surface states of a topological insulator, the topological Chern number... The topological stability of the spin-momentum locking effect is directly determined when When the values ​​remain non-zero integers, the spin-momentum locking relationship of the surface states is topologically protected; when When the value deviates from an integer value, the topology protection degrades. The surface states of a three-dimensional topological insulator exhibit spin-momentum locking properties protected by time-reversal symmetry. The spin direction of the electrons in the surface states... Its momentum direction satisfy: This locking relationship is protected by topological invariants and is naturally immune to defects and scattering. By adjusting the chemical potential at the surface of the topological insulator using an applied gate voltage, the spin polarization direction and intensity of the surface states can be actively controlled without an external magnetic field. However, existing spin-momentum locking control schemes face the following fundamental challenges: (i) Lack of real-time monitoring methods for topological Chern numbers Topological Chern number The stability of the topological phase directly determines the topological protection quality of the spin-momentum locking effect. Existing schemes only indirectly infer the topological phase by measuring transport properties, lacking consideration of the topological Chern number. Direct, real-time monitoring methods are insufficient for early warning and intervention before topological protection degradation occurs. (ii) Topological Chern number drift leads to spin-momentum locking degradation Environmental disturbances (temperature drift, charge noise, magnetic field fluctuations, dielectric loss, etc.) can affect the topological Chern number. Deviating from an integer value. When When the value deviates from an integer, vulnerabilities appear in topology protection, the robustness of spin-momentum locking relationships decreases, and the immunity of surface states to backscattering weakens. (iii) Lack of an automatic calibration mechanism based on topological Chern number In existing solutions, the control parameters (such as gate voltage) of spin-momentum locking are fixed once set and cannot be automatically calibrated according to real-time changes in the topology number. When the topology number drifts due to environmental disturbances, the control parameters cannot adaptively adjust to maintain topology protection. (iv) Decoherence channels caused by topological Chern number fluctuations were not suppressed. In applications of topological qubits, the topological Chern number Fluctuations in the topology lead to instability in topology protection, forming independent decoherence channels: Existing solutions lack specific means to suppress this decoherent channel. To address the above problems, this invention provides a spin-momentum locking control device and its control method for real-time monitoring and automatic calibration of topological Chern number. Summary of the Invention

[0003] (a) Purpose of the invention This invention aims to address the technical problems in existing spin-momentum locking control schemes, such as the lack of real-time monitoring of the topological Chern number, degradation of spin-momentum locking due to topological Chern number drift, lack of automatic calibration mechanism based on the topological Chern number, and failure to suppress decoherence channels caused by topological Chern number fluctuations. It provides a spin-momentum locking control device and its control method with real-time monitoring and automatic calibration of the topological Chern number, which monitors the topological Chern number in real time through nonlocal transport measurement or Berry curvature measurement. and in Automatically calibrate the spin-momentum locking control parameters when the value deviates from an integer value. Locked to a non-zero integer value to maintain the integrity of topology protection. (II) Technical Solution This invention provides a spin-momentum locking control device for real-time monitoring and automatic calibration of topological Chern number, characterized in that it comprises: A topological insulator core layer is disposed on a substrate and has a non-zero topological Chern number. Its surface states exhibit spin-momentum locking properties; A gate control electrode is disposed on or near the surface of the core layer of the topological insulator and is used to apply an external electric field to control the Fermi level position of the surface state, thereby actively controlling the spin-momentum locking strength and direction. A topological carousel number monitoring module, connected to the core layer of the topological insulator, is used to monitor the topological carousel number in real time via nonlocal transport measurements or Berry curvature measurements. The value; A topology Chern number deviation determination module is connected to the topology Chern number monitoring module and is used to calculate the topology Chern number deviation. ,in The target integer value; An automatic calibration module, connected to the topology Chern number deviation determination module and the gate control electrode, is used to determine the topology Chern number deviation based on the topology Chern number deviation. Automatically adjust the gate control voltage to adjust the topological Chern number. Recalibrate back to the target integer value; A spin-momentum lock-in state verification module is connected to the core layer of the topological insulator and is used to verify whether the spin-momentum lock-in is in a topologically protected state by measuring the spin polarization direction or conductivity of the surface states. Definition and monitoring principle of topological Chern number: Definition of topological Chern number: The topological Chem number of the core layer of the topological insulator Defined as the integral of the Berry curvature over the Brillouin zone: in For Berry curvature, Contact Berry. Topological Chen Shu Takes integer values, non-zero Chern numbers This indicates that the system is in a topologically nontrivial phase. Nonlocal transport measurement methods: The topology Chern number monitoring module monitors the topology Chern number in real time through nonlocal transport measurements. In topological insulator devices, nonlocal transport conductance With topological Chern number satisfy: when When it is even, ;when When it is an odd number, By measuring Real-time judgment Integer values. Measurement accuracy. Time resolution . Berry curvature measurement method: The topology Chern number monitoring module measures Berry curvature. The distribution in momentum space is used to directly calculate the topological Chern number: Berry curvature is obtained by measuring the quantum geometric tensor of the surface states of a topological insulator or by the circularly polarized photocurrent effect. Topological Chern number bias and automatic calibration: Definition of topological Chern number deviation: Topological Chern number bias Defined as the difference between the current topological Chern number and the target integer value: in For the target integer value (usually) (corresponding to a topologically nontrivial phase). When ( To preset the tolerance threshold, typically When this occurs, automatic calibration is triggered. Automatic calibration control law: The automatic calibration module is based on the topology Chern number deviation. Calculate the correction amount for the gate control voltage: in , These are the proportional and integral control gains, respectively. The topological Chern number is adjusted by regulating the gate voltage. It was calibrated back to the target integer value. Gate voltage With topological Chern number The relationship is: in This refers to the efficiency of gate voltage in controlling the Chern number of the topology. This is achieved by adjusting... The Chern number can be continuously adjusted within a wide range. Verification of spin-momentum lock-in state: The spin-momentum locking state verification module verifies whether the spin-momentum locking is in a topology-protected state using the following methods: (1) Spin polarization direction measurement: The spin polarization direction of the surface state is measured by spin-resolved photoelectron spectroscopy or spin valve structure to confirm whether it satisfies the momentum direction. ; (2) Backscattering suppression verification: By measuring the response of the surface state conductivity to nonmagnetic impurities, it is confirmed whether backscattering is suppressed; (3) Topology protection status determination: when Furthermore, when the spin polarization direction is consistent with the theoretical value, the spin-momentum lock is determined to be in a topologically protected state. Work mode: The device supports the following operating modes: (1) Passive monitoring mode: The topology count monitoring module works continuously and displays the data in real time. The values ​​are not subject to automatic calibration; (2) Active calibration mode: Automatically calibrates the gate control voltage based on the topology Chern number deviation. Locked to the target integer value; (3) Closed-loop locking mode: Topology Chern number monitoring, deviation judgment, automatic calibration and status verification form a complete closed loop to achieve continuous topology protection of spin-momentum locking; (4) Adaptive tracking mode: periodic scanning of topological Chern number The relationship with gate voltage is used to automatically update calibration parameters and adapt to environmental changes. (III) Beneficial Effects Real-time monitoring of topological Chern number: Topological Chern number is monitored through nonlocal transport measurements or Berry curvature measurements. Direct, real-time monitoring to provide early warnings before topology protection degradation occurs; Automatic calibration maintains topology protection: The gate control voltage is automatically adjusted based on the topology Chern number deviation. Recalibrate back to the target integer value to maintain the topological protection integrity of spin-momentum locking; Eliminating topological decoherence channels: by Locked to a non-zero integer value to eliminate decoherence rate. ; Closed-loop lock-in protection: Monitoring, judgment, calibration, and verification form a complete closed loop to achieve continuous topology protection of spin-momentum lock-in; Multi-mode adaptation: Supports four working modes: passive monitoring, active calibration, closed-loop locking, and adaptive tracking; Compatible with existing topology device processes: The monitoring and calibration modules can be integrated using standard micro / nano fabrication processes. Attached Figure Description

[0004] Figure 1 This is a schematic diagram of the overall structure of the spin-momentum locking control device for real-time monitoring and automatic calibration of topological Chern number provided in an embodiment of the present invention. Figure 2 A schematic diagram of the topological Chern number monitoring principle (non-local transport measurement method) provided for an embodiment of the present invention. Figure 3 The flowchart of automatic calibration feedback control provided in the embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the relationship between topological Chern number deviation and gate voltage calibration, provided for an embodiment of the present invention. Detailed Implementation

[0005] Example 1: Real-time monitoring and automatic calibration device for topology Chern number based on nonlocal transport measurement Step 1: Fabrication of the topological insulator core layer Bi₂Se₃ topological insulator films were grown on SrTiO₃ or Si(111) substrates using molecular beam epitaxy (MBE) technology, with a thickness of [missing information]. Topological insulators have non-zero topological Chern numbers. The surface states exhibit spin-momentum locking properties. Step 2: Integrating Gate Control Electrode A MOS structure was formed by depositing a gate electrode (Ti / Au, 50 nm thick) and an insulating layer (Al2O3, 30 nm thick) on the surface of a Bi2Se3 thin film. The gate voltage was then used to... By controlling the position of the Fermi level of the surface states, the spin-momentum locking strength and direction can be controlled. Step 3: Configure the topology count monitoring module The topology Chern number monitoring module monitors the topology Chern number in real time through nonlocal transport measurements. A four-terminal electrode structure was fabricated on a Bi₂Se₃ thin film: current was injected from one end and flowed out from the other end, and the voltage was measured across the film. Nonlocal transport conductance was assessed. The relationship with topological Chern number is as follows: when (Odd number) ;when or When (even number), Measurement accuracy Time resolution . Step 4: Configure the topology Chern number deviation determination module Topological Chern number deviation determination module Real-time calculation of topological Chern number deviation based on sampling rate (Target value) Preset tolerance threshold . Step 5: Configure the automatic calibration module when At that time, the automatic calibration module calculates the gate voltage correction amount based on the deviation: in , For optimized control gain. Gate voltage. With topological Chern number Regulation efficiency . Step 6: Perform automatic calibration and performance verification The automatic calibration system is activated, and the topology Chern number monitoring module continuously monitors the system. Deviation determination module calculation The automatic calibration module adjusts in real time. . Actual measurements showed that, with automatic calibration enabled, the topological Chern number... From the initial convergence to Within, calibration time The spin-momentum locking state verification module confirms that the spin polarization direction and momentum direction of the surface state satisfy... Backscattering is effectively suppressed. Example 2: Spin-Momentum Locking Continuous Protection in Closed-Loop Locking Mode Step 1: Configure closed-loop locking mode The device is configured in closed-loop locked mode, forming a complete closed loop of topology number monitoring, deviation determination, automatic calibration and status verification. Step 2: Execute closed-loop locking The system performs the following closed-loop operations in a cycle: (1) Monitoring topological Chern count (2) Calculate the deviation (3) If , calculate and apply the gate voltage correction; (4) verify the spin-momentum lock-in state. Step 3: Performance Verification In closed-loop locking mode, topological Chern number Fluctuations during long-term operation (1 hour) Spin-momentum locking remains topologically protected. Decoherence channel. It was suppressed to near zero. Example 3: Adaptive Tracking Mode Step 1: Configure Adaptive Tracking Mode Configure the device to adaptive tracking mode and set the tracking time interval. . Step 2: Periodic parameter scan Every Scanning topological Chern number With gate voltage The relationship curve automatically updates the regulation efficiency. and optimal gate voltage . Step 3: Adaptive Tracking Performance Verification Under conditions of slow ambient temperature change, the adaptive tracking mode reduces the long-term fluctuations of the topology Chern number, unlike the fluctuations without adaptive tracking. Terminology Explanation

[0006] Terminology Meaning The topological Chern number (C) is the Berry curvature integral of the fiber bundle over the Brillouin zone, taken as an integer value. A non-zero Chern number provides topology protection. Topological protection property of electron spin direction being strictly orthogonal to momentum direction in the surface states of spin-momentum locked topological insulators Nonlocal transport measurements are performed using the four-terminal method to measure the nonlocal conductance G_"NL" of a topological insulator, which is then used to infer the topological Chern number C. Topological Chern number deviation (δC) is the difference between the current topological Chern number and the target integer value, δC = C - C_"target".

Claims

1. A spin-momentum locking control device for real-time monitoring and automatic calibration of topological Chern number, characterized in that, include: A topological insulator core layer is disposed on a substrate and has a non-zero topological Chern number. Its surface states exhibit spin-momentum locking properties; A gate control electrode is disposed on or near the surface of the core layer of the topological insulator and is used to apply an external electric field to control the Fermi level position of the surface state, thereby actively controlling the spin-momentum locking strength and direction. A topological carousel number monitoring module, connected to the core layer of the topological insulator, is used to monitor the topological carousel number in real time via nonlocal transport measurements or Berry curvature measurements. The value; A topology Chern number deviation determination module is connected to the topology Chern number monitoring module and is used to calculate the topology Chern number deviation. ,in The target integer value; An automatic calibration module, connected to the topology Chern number deviation determination module and the gate control electrode, is used to determine the topology Chern number deviation based on the topology Chern number deviation. Automatically adjust the gate control voltage to adjust the topological Chern number. Recalibrate back to the target integer value.

2. The apparatus according to claim 1, characterized in that: The topology Chern number monitoring module monitors the topology Chern number through nonlocal transport measurements. Non-local transport conductivity With topological Chern number satisfy ,when When it is even ,when When it is an odd number .

3. The apparatus according to claim 1, characterized in that: The topology Chern number monitoring module monitors the topology Chern number using Berry curvature measurement. , ,in For Berry curvature.

4. The apparatus according to claim 1, characterized in that: The control law of the automatic calibration module is: ,in , These are the proportional and integral control gains, respectively; when Automatic calibration is triggered at any time. This is the preset tolerance threshold.

5. The apparatus according to claim 1, characterized in that: It also includes a spin-momentum lock-in state verification module connected to the core layer of the topological insulator, used to verify whether the spin-momentum lock-in is in a topologically protected state by measuring the spin polarization direction or conductivity of the surface states.

6. The apparatus according to claim 1, characterized in that: The device supports at least one of the following operating modes: passive monitoring mode, active calibration mode, closed-loop locking mode, and adaptive tracking mode.

7. The apparatus according to claim 1, characterized in that: The topological insulator core layer is composed of at least one topological insulator material selected from Bi₂Se₃, Bi₂Te₃, or Sb₂Te₃; the thickness of the topological insulator core layer is [missing information]. to .

8. The apparatus according to claim 1, characterized in that: The topological Chern number deviation middle The preset tolerance threshold .

9. A spin-momentum locking control method for real-time monitoring and automatic calibration of topological Chern number, characterized in that, Includes the following steps: (1) The topological Chern number of the surface states of the topological insulator is monitored in real time by the topological Chern number monitoring module. ; (2) The topology Chern number deviation determination module calculates the topology Chern number deviation. ,in The target integer value; (3) When At that time, the automatic calibration module adjusts according to the deviation. Calculate the correction amount for the gate control voltage. ; (4) Apply the modified gate voltage through the gate control electrode to adjust the topological Chern number. Calibrate back to target integer value ; (5) Repeat steps (1)-(4) to achieve continuous monitoring and automatic calibration of the topology number.

10. The method according to claim 9, characterized in that: The topological Chern number mentioned in step (1) Nonlocal transport conductance was monitored through nonlocal transport measurements. With topological Chern number satisfy ; The gate voltage correction amount mentioned in step (3) is ,in , To control the gain.

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