Current standard source device based on quantum effect

Abstract

The invention relates to a current standard source device based on a quantum effect. The current standard source device comprises a first microwave source, a first programmable Josephson voltage standard module, a first quantum Hall resistor module and a low-temperature resistance comparator. The first microwave source is used for generating first microwaves provided for the first programmable Josephson voltage standard module; the first programmable Josephson voltage standard module is directly coupled with the first quantum Hall resistor module and is used for generating adjustable quantization voltage according to the frequency of the first microwave and loading the adjustable quantization voltage on the first quantum Hall resistor module to form quantization current; and the low-temperature resistance comparator is respectively connected with the first quantum Hall resistance module and an external current source, and is used for comparing the quantized current with the current generated by the external current source to form an output current. According to the invention, errors of series resistors and contact resistors in traditional double-line connection can be eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of quantum current sources, and in particular to a current standard source device based on quantum effects. Background Art

[0002] As the core foundation of modern precision electrical metrology, quantum current standards play an irreplaceable role in instrument calibration, reference transfer, and quantum metrology research. The current technology system mainly relies on the coordinated implementation of single-electron devices and macroscopic quantum effects. Among them, the quantum current source based on the single-electron tunneling effect can achieve femtoampere-level accuracy, but its output range is limited by the physical limit of the quantum tunneling rate and it is difficult to meet the industrial-grade milliampere range requirements. The solution based on the combination of quantum Hall resistance and Josephson voltage standard can indirectly reproduce the current through Ohm's law, but due to the introduction of systematic errors due to parasitic parameters such as contact resistance and thermoelectric potential, it still needs to rely on complex extrapolation correction models.

[0003] With the full traceability of the International System of Units (SI) to quantum standards, high-precision, wide-range current standards have become a core requirement for supporting advanced manufacturing (such as beam control in semiconductor processes) and high-energy physics (such as particle detector calibration). Quantum current standards use the synergistic effect of the Josephson effect and the quantum Hall effect to combine microwave frequency-tuned quantized voltage (V = n(h / 2e)f) with quantum Hall resistance (R H =h / 2e 2 ) can be traced back to the quantum current of the fundamental constants h and e, and can achieve 10 in the 1μA-10mA range. -8 The relative uncertainty of the quantum current source is improved, breaking the contradiction between the range and accuracy in traditional technologies. Its applications have covered scenarios such as the reconstruction of electrical metrology systems (such as the quantization reproduction of SI amperes and the verification of quantum metrology triangle closure), industrial detection (semiconductor nanobeam control, biosensor TΩ-level impedance measurement) and cutting-edge scientific research (topological insulator quantum transport research, superconducting quantum bit manipulation). Existing technologies face a significant contradiction: the improvement of the accuracy of quantum current sources usually comes at the expense of the range, while extending the range will introduce nonlinear errors that are difficult to eliminate. For example, when a traditional quantum current device outputs at the milliampere level, its uncertainty will deteriorate to 10 due to the thermal noise of the resistor network and the discrete design of the quantum reference. -6 This severely restricts applications in high-precision scenarios such as superconducting quantum bit manipulation and nanoelectronic device testing. Furthermore, existing devices often use discrete cryogenic module designs, resulting in low system integration, high operating costs, and difficulty in dynamically adjusting current parameters. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a current standard source device based on quantum effect, which can eliminate the series resistance error of traditional two-wire connection.

[0005] The technical solution adopted by the present invention to solve the technical problem is: providing a current standard source device based on quantum effect, including: a first microwave source, a first programmable Josephson voltage standard module, a first programmable quantum Hall resistance module and a low-temperature resistance comparator;

[0006] The first microwave source is used to generate a first microwave provided to the first programmable Josephson voltage standard module;

[0007] The first programmable Josephson voltage standard module is directly coupled to the first quantum Hall resistance module, and the first programmable Josephson voltage standard module is used to generate an adjustable quantized voltage according to the frequency of the first microwave, and load the voltage on the first quantum Hall resistance module to form a quantized current;

[0008] The low-temperature resistance comparator is connected to the first quantum Hall resistance module and the external current source respectively, and is used to compare the quantized current with the current generated by the external current source to form an output current.

[0009] The first programmable Josephson voltage standard module and the first programmable quantum Hall resistance module are directly coupled through a superconducting cable.

[0010] The first programmable quantum Hall resistance standard module includes:

[0011] An array of Hall bar devices arranged in an M×N matrix, wherein adjacent Hall bar devices in the array are connected in series in a triple manner to form a basic unit, wherein each basic unit is connected in such a manner that a current output end of a preceding Hall bar device and two equipotential voltage terminals of a succeeding Hall bar device are symmetrically coupled via an NbN superconducting wire, a current input end of each Hall bar device and two equipotential voltage terminals of an adjacent Hall bar device are connected via three symmetrical NbN superconducting paths to form a topological closed loop, and a shunt current at the third contact is only (r / R) times the current of the first contact. H ) 2 , r is the contact interface resistance, R H is the quantum resistance value of a single Hall bar device;

[0012] a first gating module configured to select input nodes of Hall bar devices in a specific row in the Hall bar device array;

[0013] a second gating module configured to select output nodes of Hall bar devices in a specific column of the Hall bar device array;

[0014] The first gating module and the second gating module cooperate to achieve quantized adjustment of the equivalent resistance of the Hall bar device array.

[0015] The first programmable quantum Hall resistance module provides quantized resistance under a magnetic field based on epitaxial graphene on a silicon carbide substrate.

[0016] The low-temperature resistance comparator is composed of a superconducting winding and a SQUID magnetic flux sensor.

[0017] The programmable quantum voltage standard is composed of a binary-divided 1VNbN / TaN / NbN Josephson junction array.

[0018] The current standard source device based on quantum effect further includes: a quantum voltmeter, which is used to perform self-verification on the output current.

[0019] The quantum voltmeter includes a second microwave source, a second programmable Josephson voltage standard module and a zero detector;

[0020] The second microwave source is used to generate a second microwave provided to the second programmable Josephson voltage standard module;

[0021] The second programmable Josephson voltage standard module is used to generate an adjustable quantized detection voltage according to the frequency of the second microwave;

[0022] The zero detector is used to compare the adjustable quantized detection voltage with the voltage generated after the output current passes through the second programmable quantum Hall resistance module, and adjust the frequency of the second microwave to make the output of the zero detector zero.

[0023] The second programmable quantum Hall resistance module provides quantized resistance under a magnetic field based on epitaxial graphene on a silicon carbide substrate, and has a resistance value equal to that of the quantized resistance provided by the first programmable quantum Hall resistance module.

[0024] The first programmable Josephson voltage standard module and the second programmable Josephson voltage standard module share a same DC bias source.

[0025] Beneficial effects

[0026] Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages and positive effects compared to the prior art: the present invention directly couples the Josephson voltage with the quantum Hall resistance via a superconducting cable. The programmable quantum Hall resistance standard, through the synergistic effect of superconducting interconnections and a triple-connection architecture, eliminates the error effects of series cable resistance and contact resistance, eliminating the need for classical error correction. The low-temperature current comparator of the present invention combines a SQUID flux sensor with a superconducting ring shield to achieve high-sensitivity detection of ampere-turn balance, reducing the uncertainty of closed-loop control current output. Furthermore, through the dynamic combination of the number of Josephson junctions, microwave frequency, and turns ratio, continuous current adjustment from microamperes to milliamperes is achieved, compatible with industrial calibration requirements at the microampere to milliampere level. The present invention also includes a quantum voltmeter that uses a second Josephson standard and a zero detector to form a balanced frequency method, achieving self-verification of current output. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 1 is a schematic structural diagram of a current standard source device based on quantum effect according to an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the circuit structure of a quantum current generator in an embodiment of the present invention;

[0029] Figure 3 Schematic diagram of a Hall bar device array in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0031] The embodiment of the present invention relates to a current standard source device based on quantum effect, such as Figure 1 As shown, it includes: a first microwave source, a first programmable Josephson voltage standard module, a first programmable quantum Hall resistance module and a low-temperature resistance comparator. The above components form a programmable quantum current generator.

[0032] The first microwave source is used to generate a first microwave provided to the first programmable Josephson voltage standard module.

[0033] The first programmable Josephson voltage standard module and the first programmable quantum Hall resistance module are directly coupled through a superconducting cable.

[0034] like Figure 2 and Figure 3As shown, in this embodiment, the first programmable quantum Hall resistance standard module includes: an array of Hall bar devices arranged in an M×N matrix, a first gating module and a second gating module, wherein M and N are positive integers.

[0035] Adjacent Hall bar devices in the Hall bar device array are connected in series in a triple manner to form a basic unit. The connection mode of each basic unit is as follows: the current output end of the preceding Hall bar device and the two equipotential voltage terminals of the succeeding Hall bar device are symmetrically coupled via NbN superconducting wires, the current input end of each Hall bar device and the two equipotential voltage terminals of the adjacent Hall bar device are connected via three symmetrical NbN superconducting paths to form a topological closed loop, and the shunt current of the third contact is only (r / R) times the current of the first contact. H ) 2 , r is the contact interface resistance, R H is the quantum resistance of a single Hall bar device, so the effect of contact resistance can be reduced to (r / R H ) 3 In this embodiment, the resistance of the contact area between the NbN superconducting wire and the Hall bar device is less than 10 -9 Ω.

[0036] In this embodiment, each Hall bar device in the Hall bar device array is provided with a switchable output pin. The first gating module is configured to select the input node of the Hall bar device in a specific row in the Hall bar device array; the second gating module is configured to select the output node of the Hall bar device in a specific column in the Hall bar device array. Through the coordinated operation of the first gating module and the second gating module, the equivalent resistance of the Hall bar device array can be quantized and adjusted in the range of 100Ω to 12906.4Ω. In this embodiment, the equivalent resistance value R of the programmable quantum Hall resistance standard module QHRS Satisfaction: R QHRS =(M / N)·R H .

[0037] It can be seen that the use of programmable quantum Hall resistance standard provides an additional degree of freedom for the adjustable output of quantum current, and works together with the programmable Josephson voltage standard to achieve flexible output of multi-valued quantum current.

[0038] In this embodiment, the second gating module of the first quantum Hall resistance module is connected to the low temperature resistance comparator (CCC) through a superconducting winding, and is connected to the other end of the first programmable Josephson voltage standard module to form a closed loop; wherein the ampere-turn balance feedback mechanism of the low temperature resistance comparator (N1I1=N2I PQCG ) Ensure that the current ratio strictly follows the theoretical value.

[0039] The triple connection circuit of the programmable quantum Hall resistance standard module in this embodiment can reduce the error caused by series resistance to 10 -10 The symmetrical connection and superconducting shielding design suppress electromagnetic environment noise and leakage current interference, and improve system stability.

[0040] In this embodiment, the first programmable quantum Hall resistor module provides quantized resistance under a magnetic field based on epitaxial graphene on a silicon carbide substrate. The first programmable quantum voltage standard is composed of a binary 1VNbN / TaN / NbN Josephson junction array, which is used to generate an adjustable quantized voltage based on the frequency of the first microwave, that is, V = nfΦ0, where V is the generated adjustable quantized voltage, f is the frequency of the first microwave, n is an integer step, and Φ0 is the magnetic flux quantum. By applying the adjustable quantized voltage V to the first quantum Hall resistor module, a quantized current can be generated.

[0041] The low-temperature resistance comparator in this embodiment is connected to the first programmable quantum Hall resistance module and the external current source, respectively, and is configured to compare the quantized current with the current generated by the external current source to generate an output current. The low-temperature resistance comparator is composed of a superconducting winding and a SQUID magnetic flux sensor.

[0042] When the resulting quantized current passes through the superconducting winding, it generates a first magnetic field. When an external current source passes through the superconducting winding, it generates a second magnetic field. The SQUID flux sensor detects the changes in these two magnetic fields. When there is a difference between the two, that is, an ampere-turn balance error, a feedback adjustment current is generated based on this error signal to adjust the external current source. The current after the external current source is fed back into the superconducting winding, reducing the ampere-turn balance error. When ampere-turn balance is achieved, the current generated by the external current source becomes the output current. This embodiment combines the SQUID flux sensor with the superconducting winding to achieve highly sensitive detection of ampere-turn balance, reducing the uncertainty of the closed-loop control current output, and thus achieving precise control of the output current.

[0043] It can be seen that this embodiment can achieve continuous adjustment of current from microamperes to milliamperes through the dynamic combination of the number of Josephson junctions of the first programmable Josephson voltage standard module, the microwave frequency generated by the first microwave source, and the turns ratio of the superconducting winding, which is compatible with the industrial calibration requirements of microamperes to milliamperes.

[0044] The current standard source device based on quantum effect in this embodiment further includes a quantum voltmeter for self-verification of the output current. The quantum voltmeter includes a second microwave source, a second programmable Josephson voltage standard module, and a zero detector.

[0045] The second microwave source is used to generate a second microwave provided to the second programmable Josephson voltage standard module.

[0046] The second programmable Josephson voltage standard module is used to generate an adjustable quantized detection voltage according to the frequency of the second microwave. In this embodiment, the second programmable Josephson voltage standard module and the first programmable Josephson voltage standard module share the same DC bias source.

[0047] The zero detector is configured to compare the adjustable quantized detection voltage with the voltage generated after the output current passes through a second programmable quantum Hall resistor module, and adjust the frequency of the second microwave to zero the output of the zero detector. The second programmable quantum Hall resistor module provides quantized resistance under a magnetic field based on epitaxial graphene on a silicon carbide substrate, and has a resistance equal to that provided by the first programmable quantum Hall resistor module.

[0048] The process of self-verification of the output current by the quantum voltmeter in this embodiment is as follows:

[0049] First, a second microwave source generates a second microwave at the same frequency as the first. The second programmable Josephson voltage standard module then generates an adjustable quantized detection voltage based on the frequency of the second microwave. A zero detector then compares this adjustable quantized detection voltage with the voltage generated by the output current passing through the second programmable quantum Hall resistor module in real time. If the adjustable quantized detection voltage and the voltage generated by the output current passing through the second programmable quantum Hall resistor module are completely consistent, the zero detector's output will remain stable, indicating that the output current is accurate and self-verified. If there is a discrepancy, the zero detector outputs an error signal, which can be detected by the control circuit, which then adjusts the second microwave source until the zero detector output indicates consistency. The frequency difference between the second and first microwave sources can then be used to determine the deviation of the programmable quantum current generator.

[0050] Even standard resistors have the problem of long-term drift or calibration error. The load in this embodiment uses a second programmable quantum Hall resistor module. Since the quantum Hall resistor module is only related to the natural constants h and e, compared with the load using a standard 100Ω resistor, this embodiment does not require additional external calibration.

[0051] It is not difficult to find that the present invention directly couples the Josephson voltage and the quantum Hall resistance through a superconducting cable. The programmable quantum Hall resistance standard eliminates the error influence of the series cable resistance and the contact resistance through the synergistic effect of superconducting interconnection and triple connection architecture, and does not require classical error correction. The low-temperature current comparator in the present invention combines the SQUID flux sensor and the superconducting ring shield to achieve high-sensitivity detection of ampere-turn balance and reduce the uncertainty of closed-loop control current output. At the same time, through the dynamic combination of the number of Josephson junctions, microwave frequency and turns ratio, continuous adjustment of current from microamperes to milliamperes is achieved, which is compatible with industrial calibration requirements at the microampere to milliampere level.

Claims

1. A current standard source device based on quantum effect, characterized in that: include: the first microwave source, the first programmable Josephson voltage standard module, the first programmable quantum Hall resistance module, and a low-temperature resistance comparator; The first microwave source is used to generate a first microwave provided to the first programmable Josephson voltage standard module; the first programmable Josephson voltage standard module and the first programmable quantum Hall resistance module are directly coupled, and the first programmable Josephson voltage standard module is used to generate an adjustable quantized voltage according to the frequency of the first microwave, and load the voltage on the first programmable quantum Hall resistance module to form a quantized current; The low-temperature resistance comparator is connected to the first programmable quantum Hall resistance module and the external current source respectively, and is used to compare the quantized current with the current generated by the external current source to form an output current.

2. The current standard source device based on quantum effect according to claim 1, characterized in that: The first programmable Josephson voltage standard module and the first programmable quantum Hall resistance module are directly coupled through a superconducting cable.

3. The current standard source device based on quantum effect according to claim 1, characterized in that: The first programmable quantum Hall resistance standard module includes: An array of Hall bar devices arranged in an M×N matrix, wherein adjacent Hall bar devices in the array are connected in series in a triple manner to form a basic unit, wherein each basic unit is connected in such a manner that a current output end of a preceding Hall bar device and two equipotential voltage terminals of a succeeding Hall bar device are symmetrically coupled via an NbN superconducting wire, a current input end of each Hall bar device and two equipotential voltage terminals of an adjacent Hall bar device are connected via three symmetrical NbN superconducting paths to form a topological closed loop, and a shunt current at the third contact is only (r / R) times the current of the first contact. H ) 2 , r is the contact interface resistance, R H is the quantum resistance value of a single Hall bar device; a first gating module configured to select input nodes of Hall bar devices in a specific row in the Hall bar device array; The second gating module is configured to select the output node of the Hall bar device in a specific column in the Hall bar device array; wherein the first gating module and the second gating module cooperate to achieve quantized adjustment of the equivalent resistance of the Hall bar device array.

4. The current standard source device based on quantum effect according to claim 1, characterized in that: The first programmable quantum Hall resistance module provides quantized resistance under a magnetic field based on epitaxial graphene on a silicon carbide substrate.

5. The current standard source device based on quantum effect according to claim 1, characterized in that: The low-temperature resistance comparator is composed of a superconducting winding and a SQUID magnetic flux sensor.

6. The current standard source device based on quantum effect according to claim 1, characterized in that: The programmable quantum voltage standard is composed of a binary-divided 1VNbN / TaN / NbN Josephson junction array.

7. The current standard source device based on quantum effect according to claim 1, characterized in that: Also includes: A quantum voltmeter is used to self-verify the output current.

8. The current standard source device based on quantum effect according to claim 7, characterized in that: The quantum voltmeter includes a second microwave source, a second programmable Josephson voltage standard module and a zero detector; The second microwave source is used to generate a second microwave provided to the second programmable Josephson voltage standard module; The second programmable Josephson voltage standard module is used to generate an adjustable quantized detection voltage according to the frequency of the second microwave; The zero detector is used to compare the adjustable quantized detection voltage with the voltage generated after the output current passes through the second programmable quantum Hall resistance module, and adjust the frequency of the second microwave to make the output of the zero detector zero.

9. The current standard source device based on quantum effect according to claim 8, characterized in that: The second programmable quantum Hall resistance module provides quantized resistance under a magnetic field based on epitaxial graphene on a silicon carbide substrate, and has a resistance value equal to that of the quantized resistance provided by the first programmable quantum Hall resistance module.

10. The current standard source device based on quantum effect according to claim 8, characterized in that: The first programmable Josephson voltage standard module and the second programmable Josephson voltage standard module share a same DC bias source.

Images