A quantum magnetic marker based on an interlayer weakly coupled device and a preparation method thereof

Abstract

The present invention belongs to the technical field of quantum physics and quantum measurement, and particularly relates to a quantum magnetic scale based on an interlayer weakly coupled device and a preparation method thereof. To achieve high-precision calibration of the magnetic field strength in a low-temperature and strong magnetic field environment, under the conditions of low temperature (for example: temperature T = 5K and below) and strong vertical magnetic field strength (magnetic field strength B = 5T and above), by using the quantization phenomenon of the ratio of the difference in the interlayer displacement electric field to the magnetic field strength in the quantized checkerboard formed by the quantization of the Landau level crossing of the longitudinal resistance in a large-angle twisted graphene system, a linear scaling relationship between the magnetic field and the difference in the interlayer displacement electric field, δD / B = e<supgt;2< / supgt; / h, is established to achieve the calibration of the magnetic field strength B.

Description

Technical Field

[0001] The present invention belongs to the technical field of quantum physics and quantum measurement, and particularly relates to a quantum magnetic scale based on an interlayer weakly coupled device and a preparation method thereof. Background Art

[0002] Magnetic field strength is one of the important physical quantities in nature, and how to measure magnetic field strength has wide application value in the field of modern science and technology. For example, high-precision magnetic field measurement plays a crucial role in fields such as physics, materials science, geological exploration, medical imaging, and industrial inspection. The accurate measurement and calibration of magnetic fields rely on high-performance magnetic scales (magnetic field calibration devices), and the working principles of magnetic scales can be calibrated Hall magnetic field sensors, nuclear magnetic resonance field measuring instruments, etc. With the increasing demand for high-precision magnetic field measurement in extreme environments, researching and developing magnetic scales with higher precision, sensitivity, and applicability to extreme environments such as strong magnetic fields, extremely low temperatures, and ultra-high pressures has become an important direction in the research of physics and metrology.

[0003] Traditional magnetic field calibration techniques rely on a series of mature methods, such as nuclear magnetic resonance (NMR) magnetic scales and superconducting quantum interference devices (SQUIDs), which are commonly used for high-precision magnetic field measurement. The nuclear magnetic resonance technique realizes magnetic field calibration by measuring the linear relationship between the Larmor precession frequency of atomic nuclei in a magnetic field and the magnetic field strength. The advantages of this method include high stability and high measurement accuracy (the accuracy can reach the order of 1 ppm, and the linearity can reach the order of 0.1 ppm). However, the nuclear magnetic resonance technique has extremely high requirements for magnetic field uniformity, and the equipment is complex, the probe volume is large, and usually the spatial resolution of the field is not high. At the same time, the nuclear magnetic resonance system is expensive and has high maintenance costs, making it difficult to meet the requirements of portability and miniaturization. A superconducting quantum interference device (SQUID) is a high-sensitivity magnetic flux measurement device. When used for weak magnetic field measurement, it is necessary to first calibrate the effective area of the magnetic flux coupling coil. And since the SQUID belongs to a non-linear device, it is extremely vulnerable to environmental magnetic field interference, resulting in the magnetic flux locked loop losing lock and unable to work properly. This limits the SQUID to only work in a laboratory environment with a good magnetic shielding environment, greatly restricting its application range. The limitations of these traditional magnetic scale techniques have prompted researchers to explore new magnetic scales based on quantum phenomena, especially for applications in extreme environments such as low temperatures and strong magnetic fields. Quantum phenomena can provide higher precision and a wider range of applicable magnetic field measurements and calibrations.

[0004] Graphene is a new type of two-dimensional material that has made breakthrough progress in the field of nanomaterials in recent years. It has unique physical properties, including ultra-high electrical conductivity, mechanical strength, flexibility, and transparency. The electronic band structure of graphene can form the quantum Hall effect at low temperatures and strong magnetic fields. This phenomenon provides a theoretical basis for the high-precision quantization calibration of magnetic fields. The quantum Hall effect refers to the fact that in a low-temperature and strong magnetic field environment, the electron motion in a two-dimensional electron system is restricted to Landau levels, and the electron conductance shows quantized jumps. For an ideal two-dimensional system, the conductivity is quantized and has a clear relationship with the Planck constant h and the electron charge: σ = e 2 / h * N, where N is a quantized integer value. Based on this quantized conductivity, it is expected to achieve a high-precision calibration method for magnetic fields traceable to fundamental physical constants and realize in-situ calibration of low-temperature and strong magnetic fields. Therefore, exploring a new type of measurement and standard quantum magnetometer based on the graphene system with the ability of in-situ magnetic field calibration has very broad application prospects. Summary of the Invention

[0005] The purpose of the present invention is to provide an interlayer weakly coupled device and its preparation method. Materials with high mobility characteristics at low temperatures, such as two-dimensional layered graphene, are used as the intermediate core layer material of the corner system to realize an interlayer weakly coupled large-angle corner double-gate device.

[0006] Another purpose of the present invention is to provide a quantum magnetic scale based on this device and its preparation method. Based on the quantization principle of the ratio of the critical displacement electric field and magnetic field for interlayer charge transfer at the quantized Landau level crossing of the interlayer weakly coupled large-angle corner system, it is a new type of quantum magnetic scale that can be widely used in quantum technology, precision measurement, and high-field physical experiments, especially suitable for magnetic field strength calibration in extremely low-temperature and strong magnetic field extreme environments.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] On the one hand, the present invention provides an interlayer weakly coupled device, which includes a substrate, a bottom gate, a bottom encapsulation layer, a large-angle interlayer corner layer, and a top encapsulation layer arranged in sequence from bottom to top. A plurality of contact electrodes are arranged on both sides of the top encapsulation layer to form an ohmic contact with the large-angle interlayer corner layer, and an insulating dielectric layer and a top gate are sequentially arranged on the top encapsulation layer.

[0009] Further, the thickness of the large-angle interlayer corner layer is not greater than 100 nm. A hetero- or homo-junction system prepared using two layers of materials with high mobility at low temperatures, such as multi-layer graphene, transition metal chalcogenides, and other two-dimensional materials with high mobility, can be selected as two-dimensional layered graphene. A large-angle corner is achieved between the two layers of two-dimensional layered graphene through van der Waals interaction.

[0010] Furthermore, the large-angle interlayer twisted layer uses two layers of two-dimensional layered graphene, and a large-angle twist is achieved through van der Waals interaction between the two layers of two-dimensional layered graphene.

[0011] Furthermore, the substrate is one of a SiO2 substrate, a Si substrate, a SiC substrate, a quartz substrate, a mica sheet, or a flexible substrate.

[0012] Furthermore, the bottom gate, the top gate, and the contact electrodes are all made of conductive materials, such as one or more of Bi, Cr, Ti, Au, Pd, Sc, Ag, Ni, and few-layer graphene. The bottom encapsulation layer, the top encapsulation layer, and the insulating dielectric layer are all made of insulator materials, and hexagonal boron nitride, HfLaO, HfO2, or Al2O3, etc. can be used.

[0013] Furthermore, the thickness of the bottom gate and the top gate is 1 nm to 1000 nm, the thickness of the bottom encapsulation layer is 1 nm to 100 nm, and the thickness of the top encapsulation layer is 10 nm to 100 nm.

[0014] In a second aspect, the present invention provides a method for manufacturing an interlayer weakly coupled device, including the following steps:

[0015] Step 1, fabricate a bottom gate and a bottom encapsulation layer on the substrate;

[0016] Step 2, transfer the large-angle interlayer twisted layer and the top encapsulation layer onto the bottom encapsulation layer to form a heterostructure;

[0017] Step 3, after patterning the heterostructure into a Hall bar shape, fabricate contact electrodes on the heterojunction;

[0018] Step 4, sequentially fabricate a top encapsulation layer and a top gate on the top, and thus an interlayer weakly coupled device (a double-gate tunable device that can measure transverse and longitudinal resistances) is fabricated.

[0019] Furthermore, the fabrication of the bottom encapsulation layer, the large-angle interlayer twisted layer, the top encapsulation layer, and the insulating dielectric layer all utilize van der Waals forces. The heterostructure is patterned into a Hall bar shape by electron beam lithography combined with reactive ion etching, and the bottom gate, the top gate, and the contact electrodes are fabricated by metal evaporation.

[0020] In a third aspect, the present invention provides a quantum magnetic scale based on an interlayer weakly coupled device. Under low-temperature (T = 5 K and below) and strong vertical magnetic field (B = 5 T and above) conditions, a linear scaling relationship between the magnetic field and the difference in displacement electric field is established by using the quantization phenomenon of the ratio of the difference in interlayer displacement electric field between two adjacent cross peaks in a quantized checkerboard formed by the quantization of Landau levels of the longitudinal resistance in the interlayer weakly coupled device, so as to achieve high-precision calibration of the magnetic field strength in a low-temperature and strong magnetic field environment.

[0021] Under the condition of continuously increasing the vertical magnetic field strength, each crossing point will evolve into a four-by-four quantized Landau level crossing matrix due to the splitting of spin and valley, that is, a quantized checkerboard electron state with four-by-four crossing points is presented. In such a checkerboard unit of uniform size, along the vertical electric field direction (defined as the y direction), the ratio of the electric field difference δD between each pair of adjacent high-resistance lattice points (this lattice point is at the junction of two adjacent quantum Hall filling states) to the vertical magnetic field B at this time is a quantized value, that is, δD / B = e 2 / h (e is the elementary charge and h is the Planck constant). The physical reason is that on the premise that the total filling coefficient of the double-layer Landau levels remains unchanged, the ratio of the critical condition of the electric field driving the interlayer charge transfer between two adjacent crossing points to the magnetic field strength satisfies that the unit charge is proportional to the unit quantum magnetic flux. And in such a checkerboard unit of uniform size, along the carrier concentration (or quantum filling coefficient) direction (defined as the x direction), the difference between adjacent filling coefficients is also quantized to be an integer multiple of e 2 / h. Therefore, each four-by-four checkerboard unit has the same size in both the x and y directions.

[0022] The quantized checkerboard can be obtained by the following method: Under low-temperature magnetic field, measure the longitudinal resistance in the parameter space of the interlayer displacement electric field and carrier concentration of the double-gate structure device.

[0023] For a checkerboard with all or part being quantized, calibration is carried out under a lower magnetic field to obtain the actual electric displacement vector value after correction of the interlayer quantum capacitance. The slope of the linear fit between the calibrated δD and B should be the von Klitzing constant. After calibration of this device, under an unknown low-temperature strong magnetic field, by measuring the difference between adjacent high-resistance state lattice points of the checkerboard along the interlayer electric field direction, the actual unknown magnetic field strength to be measured can be directly obtained.

[0024] Furthermore, by measuring the differences between adjacent high-resistance state lattice points of multiple said checkerboards along the interlayer electric field direction multiple times, the accuracy can be improved.

[0025] In a fourth aspect, the present invention provides a preparation method of a quantum magnetic scale based on an interlayer weakly coupled device, including the following steps:

[0026] Step 1: Characterize the basic parameters of the interlayer weakly coupled device through low temperature, weak vertical magnetic field or strong vertical magnetic field;

[0027] Step 2: Conduct a standard four-terminal method AC analysis test, set up a test system for the longitudinal resistance varying with the dual-gate voltage or carrier concentration and the interlayer displacement electric field. By measuring the displacement electric field difference δD between the nearest-neighbor intersections of the four-by-four Landau level crossing quantization checkerboard where the layer polarization, spin polarization, and valley polarization are all degenerate, calibrate the magnetic field strength B in the extreme environments of low temperature and strong magnetic field through the formula B = h / e 2 *δD, where e is the unit charge and h is the unit quantum magnetic flux.

[0028] Use interlayer weakly coupled large-angle twisted graphene as the basic unit. At the Landau level crossing under low temperature and strong magnetic field, the layer, spin, and valley polarizations are completely degenerate, forming a four-by-four Landau level crossing matrix. On the premise that the Landau level filling factor remains unchanged in the fixed twist system, the ratio of the critical electric field δD driving the interlayer charge transfer between two adjacent Landau level crossing points to the vertical magnetic field strength B satisfies that the unit charge e is proportional to the unit quantum magnetic flux (h / e), that is, e 2 / h. By measuring the displacement electric field difference δD between two adjacent Landau level crossing peaks at a certain fixed filling coefficient in the region of the four-by-four quantization matrix of the Landau level crossing in the interlayer weakly coupled large-angle twisted graphene system, and then combining the calculation formula B = h / e 2 *δD, the magnetic field strength B in the extreme environments of low temperature and strong magnetic field can be calibrated.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] 1. Suitable for low-temperature and strong magnetic field environments: The quantization phenomenon is particularly significant under low-temperature and strong magnetic field conditions, and the calibration accuracy is higher. Graphene materials have good low-temperature conductivity and mechanical strength, and are suitable for application scenarios of extremely low temperature (such as liquid helium temperature and below) and high magnetic field (five to dozens of Tesla), which provides a wider environmental adaptability for magnetic field measurement.

[0031] 2. Linear scaling relationship: Establish a linear relationship between the interlayer displacement electric field difference and the magnetic field through the quantization effect, and achieve accurate calibration within a continuous magnetic field range.

[0032] 3. High-quality encapsulation: Adopt high-quality dielectric materials such as boron nitride for encapsulation, which improves the electrical isolation performance and thermal stability of the system.

[0033] 4. Higher precision, stability, and low magnetic field calibration drift: Based on the quantization characteristics of the ratio of the interlayer displacement electric field difference to the magnetic field, the system is calibrated at low temperature and low magnetic field ranges. It can achieve quantization calibration of the magnetic field strength with near-zero drift characteristics in low-temperature and high-magnetic field environments, and can provide higher precision and long-term stability in extreme environments.

[0034] 5. Small size and high spatial resolution: Based on the weakly coupled large-angle twisted graphene system of two-dimensional materials, the in-plane and out-of-plane dimensions are in the micrometer and nanometer levels respectively. The quantum magnetic calibration system based on the above micro-nano system has the advantages of small size and high spatial resolution, and is applicable to local precision measurement, especially suitable for magnetic field measurement in microstructures.

[0035] 6. Low requirement for magnetic field uniformity: Based on the weakly coupled large-angle twisted graphene system, the in-plane and out-of-plane dimensions of the device are in the micrometer and nanometer scales. Therefore, the requirement for the uniformity of the target magnetic field is relatively low, and the applicable range is wide. It can still accurately calibrate especially under relatively non-uniform magnetic field conditions.

[0036] 7. Simple system design: Compared with the mature nuclear magnetic resonance system, the quantum magnetic calibration system has a more concise design, and is more convenient for operation and maintenance.

[0037] 8. It can conveniently realize the measurement of the uniformity of the three-dimensional space magnetic field: By designing a three-dimensional spherical or cubic sample array, the uniformity measurement of the three-dimensional space magnetic field can be realized at one time, which is convenient for solving the problem of evaluating the uniformity of the magnetic field of medical nuclear magnetic resonance imaging systems and other high-uniformity magnets.

[0038] 9. Flexibility, transparency, and wearability: The magnetic calibration system based on two-dimensional materials has unique physical properties such as flexibility, transparency, and wearability. It can adapt to deformations such as bending and torsion, and is applicable to magnetic field calibration in various environments. The transparent property of graphene enables the system to calibrate without blocking light, which is suitable for magnetic field measurement in transparent displays and other optical devices. This makes it have broad application prospects in future portable electronic devices, flexible displays, and wearable devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic structural diagram of the interlayer weakly coupled device provided by the embodiment of the present invention;

[0040] Figure 2 It is a Landau level crossing point diagram of an interlayer weakly coupled device of the embodiment of the present invention under the environment of low temperature (T = 1.6K) and perpendicular magnetic field (magnetic field strength B = 5T).

[0041] Figure 3Schematic diagram of a Landau level crossing quantization checkerboard of an interlayer weakly coupled device according to an embodiment of the present invention under a low temperature (T = 1.6 K) and a perpendicular strong magnetic field (magnetic field intensity B = 12 T).

[0042] Figure 4 Is the magnetic field calibration curve;

[0043] Figure 5 Schematic diagram of a quantum magnetic calibration test method based on an interlayer weakly coupled device. Specific implementation manner

[0044] In order to further elaborate on the technical solution of the present invention, the present invention will be further described below through embodiments.

[0045] Embodiment 1

[0046] 1) Using electron beam lithography, evaporation, PPC-assisted dry transfer technology and annealing technology, a clean bottom gate 7 / bottom encapsulation layer 6 is pre-prepared on a clean substrate 8. The annealing temperature ranges from 200 °C to 400 °C, and the vacuum holding time is greater than or equal to thirty minutes. In this embodiment, the substrate 8 uses a highly doped Si substrate, and the bottom gate 7 / bottom encapsulation layer 6 is Au / h-BN;

[0047] 2) With the help of the anodic oxidation function of the atomic force microscope, a single-layer uniform clean two-dimensional layered graphene obtained by mechanical cleavage is oxidized and cut into two independent graphene sheets, namely graphene sheet one and graphene sheet two. That is, the large-angle interlayer twist layer 5 in this embodiment uses two layers of graphene;

[0048] 3) Using the PC-assisted dry transfer technology, a viscous polymer (PDMS / PC bilayer structure) is used to lift the uniformly few-layer h-BN (10 - 60 nanometers thick) obtained by pre-mechanical cleavage and graphene one in step 2) in sequence, to obtain a four-layer structure of PDMS / PC / h-BN / graphene sheet one. That is, the top encapsulation layer 4 in this embodiment uses h-BN;

[0049] 4) Keeping the four-layer structure in step 3) stationary, the sample stage carrying graphene two is rotated through a rotation operation to achieve a rotation of a preset large-angle interlayer twist angle (for example: θ = 10 degrees, 20 degrees, 30 degrees, etc.).

[0050] 5) Using the four-layer structure obtained in step 3), lift graphene sheet two after rotation in step 4) by using interlayer van der Waals interaction to obtain a five-layer structure of PDMS / PC / h-BN / large-angle twisted bilayer graphene.

[0051] 6) By melting the five-layer structure of PDMS / PC / h-BN / large-angle twisted bilayer graphene prepared in step 5), melt the PC and transfer it onto the Au / h-BN prepared in step 1). Further clean the PC with chloroform, acetone, and isopropanol to obtain a two-dimensional stacked h-BN / large-angle twisted bilayer graphene / h-BN / Au heterostructure with clean surfaces and interfaces;

[0052] 7) Use electron beam lithography (EBL) and reactive ion etching (RIE) to pattern the device into a structure with a Hall bar shape in the middle region as shown in Figure 1 ;

[0053] 8) Use electron beam lithography (EBL) and electron beam evaporation (EB) techniques to deposit a contact electrode 3 as shown in Figure 1 on the sample patterned in step 7). The contact electrode 3 is made of Ti / Au (for example: Ti / Au = 5 / 50 nm);

[0054] 9) Use atomic layer deposition (ALD) to uniformly deposit an insulating dielectric layer 2 with a thickness of 10 nm to 50 nm on the sample surface. The insulating dielectric layer 2 is an oxide dielectric layer (such as insulating materials like alumina or hafnium oxide, etc.);

[0055] 10) Use electron beam lithography (EBL) and electron beam evaporation (EB) techniques to deposit a top gate electrode 1 as shown in Figure 1 on the sample. The top gate electrode 1 is made of metal (for example: Ti / Au = 5 / 30 nm). Thus, an interlayer weakly coupled device is fabricated;

[0056] 11) Test the device at room temperature using a probe station to characterize the transfer characteristic curve and current-voltage characteristic curve at room temperature, and check whether the contact electrode 3 of the device is in good contact and whether the device has top-gate and bottom-gate controllability;

[0057] 12) Connect the device to the sample holder using a Wire-Bonder, load it into a cryogenic vacuum chamber, cool it down to 1.5 K, and perform cryogenic four-terminal AC transport tests. Using the schematic diagram of the quantum magnetic standard test method for the interlayer weakly coupled device as shown in Figure 5 , under the condition of applying a low vertical magnetic field, obtain the characteristic curve of the longitudinal resistance varying with the dual-gate (top gate and bottom gate) voltage (or convert it into the characteristic curve varying with the carrier concentration and interlayer displacement electric field), and observe the Landau level crossing characteristics under a low vertical magnetic field (such as Figure 2 shown at a magnetic field intensity of B = 4 T);

[0058] From Figure 2It can be seen that in the quantum magnetic scale system based on the interlayer weakly coupled device, when the vertical magnetic field strength is 4T, the layer polarization of the system splits, and an obvious phenomenon of Landau level crossing appears in the system;

[0059] 13) Perform low-temperature tests on the devices inside the low-temperature vacuum chamber in a higher vertical magnetic field (such as B = 5T - 40T) environment to obtain a four-by-four Landau level crossing array or checkerboard (as Figure 3 shown) where both the spin and valley degeneracy are broken. And measure the difference δD in the direction of the interlayer displacement electric field between the nearest-neighbor Landau level crossing points in the checkerboard when the carriers are fixed (as Figure 5 shown in the δD measurement method). Through the formula B = h / e 2 *δD, calibrate the magnetic field strength B in the extreme environments of low temperature and strong magnetic field (such as Figure 4 );

[0060] From Figure 3 it can be seen that when the vertical magnetic field strength is 12T, the longitudinal resistance at low field (such as Figure 2 shown) splits into a four-by-four crossed Landau level crossing array checkerboard. The integer filling factor can be obtained along the tangent of the horizontal axis of the longitudinal resistance. Along the vertical axis direction (i.e., the ratio of the interlayer displacement electric field to the magnetic field strength), the ordinate difference between the peaks of two adjacent longitudinal resistances is e 2 / h, showing quantized behavior;

[0061] From Figure 4 it can be seen that there is a linear correlation between the magnetic field strength B and the displacement electric field difference δD, and the coefficient is the K.v.Klitzing constant;

[0062] From Figure 5 it can be seen that the specific working implementation method of the quantum magnetic scale system based on the interlayer weakly coupled device is as follows: fabricate an array of micron-sized double-gate Hall bar interlayer weakly coupled devices, use the AC four-terminal method to perform electrical transport tests on the devices under low temperature and strong magnetic field, collect the longitudinal resistance information through the computer PC side, obtain a four-by-four crossed Landau level crossing array checkerboard of the longitudinal resistance with respect to the carrier concentration and the interlayer displacement electric field strength in this environment. By measuring the displacement electric field difference δD between the peaks of two adjacent Landau level crossings at a fixed carrier concentration, through the formula B = h / e 2 *δD, calibrate the magnetic field strength B in the extreme environments of low temperature and strong magnetic field.

[0063] Example 2

[0064] The difference from Example 1 is that: the two-dimensional layered graphene described in step 2) is a material prepared by the chemical vapor deposition (CVD) method.

[0065] The obtained interlayer weakly coupled large-angle twisted graphene device can achieve the four-by-four Landau level crossing quantization phenomenon under low-temperature and strong magnetic field environments.

[0066] Example 3

[0067] The difference from Example 1 is that in step 1), the bottom gate 7 / bottom encapsulation layer 6 is Au / Al2O3, Au / HfO2, and is prepared by atomic layer deposition (ALD) method.

[0068] The obtained interlayer weakly coupled large-angle twisted graphene device can achieve the four-by-four Landau level crossing quantization phenomenon under low-temperature and strong magnetic field environments.

[0069] Example 4

[0070] The difference from Example 1 is that in step 2), by means of laser cutting, a single-layer uniform and clean graphene obtained by mechanical cleavage is cut into two independent graphene sheets, graphene sheet one and graphene sheet two.

[0071] The obtained interlayer weakly coupled large-angle twisted graphene device can achieve the four-by-four Landau level crossing quantization phenomenon under low-temperature and strong magnetic field environments.

[0072] Example 5

[0073] The difference from Example 1 is that in step 9), the insulating dielectric layer 2 is 10 nm - 60 nm of h-BN obtained by mechanical dissociation, and the above transfer is realized by dry transfer technology using a viscous polymer (PDMS single-layer material or PDMS / PC bilayer structure);

[0074] The obtained interlayer weakly coupled large-angle twisted graphene device can achieve the four-by-four Landau level crossing quantization phenomenon under low-temperature and strong magnetic field environments.

[0075] Example 6

[0076] The difference from Example 1 is that in step 8), the contact electrode 3 is one or more of metals Bi, Cr, Ti, Au, Pd, Sc, Ag, Ni, and few-layer graphene.

[0077] The obtained interlayer weakly coupled large-angle twisted graphene device can achieve the four-by-four Landau level crossing quantization phenomenon under low-temperature and strong magnetic field environments.

[0078] Example 7

[0079] The difference from Example 1 is that in step 1), the substrate 1 is a SiC substrate, a high-resistance silicon substrate, a sapphire substrate, or other flexible substrates.

[0080] The obtained interlayer weakly coupled large-angle twisted graphene device can achieve the four-by-four Landau level crossing quantization phenomenon under low temperature and strong magnetic field environments.

[0081] The foregoing has shown and described the main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes that fall within the meaning and scope of the equivalent elements of the claims within the present invention.

[0082] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing an interlayer weak coupling device, characterized in that: The following steps are involved: Step 1, preparing a bottom gate (7) and a bottom encapsulation layer (6) on a substrate (8); Step 2, transferring the large-angle interlayer corner layer (5) and the top encapsulation layer (4) to the bottom encapsulation layer (6) to form a heterogeneous structure; Step 3, after patterning the heterostructure into a Hall bar shape, a contact electrode (3) is prepared on the heterojunction; Step 4, sequentially preparing a top encapsulation layer (4) and a top gate (1) on the top, thereby obtaining an interlayer weak coupling device; The interlayer weak coupling device comprises a substrate (8), a bottom gate (7), a bottom packaging layer (6), a large-angle interlayer corner layer (5) and a top packaging layer (4) which are arranged in sequence from bottom to top; a plurality of contact electrodes (3) are arranged on both sides of the top packaging layer (4) to form ohmic contacts with the large-angle interlayer corner layer (5); an insulating dielectric layer (2) and a top gate (1) are arranged in sequence on the top packaging layer (4); the large-angle interlayer corner layer (5) uses two layers of two-dimensional layered graphene, and a large-angle corner is achieved between the two layers of two-dimensional layered graphene through van der Waals interaction.

2. The method for preparing an interlayer weak coupling device according to claim 1, characterized in that: The bottom encapsulation layer (6), the large-angle interlayer corner layer (5), the top encapsulation layer (4) and the insulating dielectric layer (2) are all prepared by utilizing van der Waals forces, and the heterostructure is patterned into a Hall bar shape by electron beam exposure combined with reactive ion etching, and the bottom gate (7), the top gate (1) and the contact electrode (3) are prepared by a metal evaporation method.

3. The method for preparing an interlayer weak coupling device according to claim 1, characterized in that: The thickness of the large-angle interlayer corner layer (5) is no more than 100 nm, and two layers of materials having high mobility at low temperatures are used.

4. The method for preparing an interlayer weak coupling device according to claim 1, characterized in that: The substrate (8) is one of a SiO2 substrate, a Si substrate, a SiC substrate, a quartz substrate, a mica sheet or a flexible substrate.

5. The method for preparing an interlayer weak coupling device according to claim 1, characterized in that: The bottom gate (7), the top gate (1) and the contact electrode (3) are all made of conductive materials, the bottom encapsulation layer (6), the top encapsulation layer (4) and the insulating dielectric layer (2) are all made of insulating materials, the thickness of the bottom gate (7) and the top gate (1) is 1 nm to 1000 nm, the thickness of the bottom encapsulation layer (6) is 1 nm to 100 nm, and the thickness of the top encapsulation layer (4) is 10 nm to 100 nm.

6. A quantum magnetic mark of an interlayer weak coupling device prepared by the preparation method according to any one of claims 1 to 5, characterized in that: Under the conditions of low temperature and strong vertical magnetic field, the linear scaling relationship between the magnetic field and the displacement electric field difference is established by utilizing the quantization phenomenon of the interlayer displacement electric field difference and the magnetic field ratio between two adjacent cross peaks in the quantized checkerboard formed by the crossover of the quantized Landau energy levels of the longitudinal resistance in the interlayer weak coupling device, thereby achieving high-precision magnetic field intensity calibration in low temperature and strong magnetic field environment.

7. The quantum magnetic marker according to claim 6, characterized in that: The accuracy is improved by measuring the difference between adjacent high-resistance grid points of the chessboard along the interlayer electric field direction for multiple times.

8. A method for preparing a quantum magnetic mark according to claim 6, characterized in that: The following steps are involved: Step 1, characterizing the basic parameters of the interlayer weak coupling device by low temperature, weak vertical magnetic field or strong vertical magnetic field; Step 2: Conduct a standard four-terminal AC analysis test, build a test system for the longitudinal resistance changing with the dual-gate voltage or carrier concentration and interlayer displacement electric field, and measure the displacement electric field difference dD between the nearest neighbor intersections of the four-by-four Landau level cross quantization chessboard with degenerate layer polarization, spin polarization, and valley polarization. h / e 2 *dD realizes the calibration of magnetic field strength B in extreme environments of low temperature and strong magnetic field, where e is the unit charge, h is the unit quantum flux.

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