One-way signal amplification topology circuit heterojunction based on Z2 skin effect

Abstract

The invention relates to the technical field of circuits, in particular to a one-way signal amplification topological circuit heterojunction based on a Z2 skin effect, which is formed by connecting a topological non-trivial region and a topological trivial region at an interface, the topological non-trivial region is a two-dimensional square circuit lattice, and in the two-dimensional square circuit lattice, the two-dimensional square circuit lattice is connected with the topological non-trivial region. Every two adjacent nodes are connected through a first coupling element or a second coupling element, each node comprises four circuit subunits, and each circuit subunit is connected with a grounding inductor or a grounding capacitor; the topological trivial area is a rectangular circuit lattice, and in the rectangular circuit lattice, every two adjacent nodes are connected through a third coupling element or a fourth coupling element; and the boundary nodes of the topological non-trivial region are connected with the boundary nodes of the topological trivial region through fifth coupling elements. Therefore, the problems that the circuit structure is complex and is easily interfered by noise due to the fact that extra gain or loss items need to be introduced for achieving the non-Hermitian topology phenomenon are solved, and the circuit has the advantages of being simple in structure and low in noise.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and in particular to a heterojunction of a unidirectional signal amplification topology circuit based on the Z2 skin effect. Background Technology

[0002] Topological insulators are a cutting-edge field of physics research in recent years. These materials have the property of "bulk state insulation and edge state conduction". Their boundary states are topologically protected, robust to local defects and disturbances, and can realize unidirectional transmission of signals (such as electrons or photons).

[0003] As research has deepened, the concept of topology has been extended to classical wave systems. For example, topological circuits composed of lumped elements such as inductors and capacitors provide a convenient way to realize and study novel topological physical phenomena on a controllable experimental platform. Meanwhile, the development of non-Hermitian physics has greatly expanded the scope of topological states of matter. Unlike energy-conserving Hermitian systems, non-Hermitian systems describe energy exchange with the environment by introducing gain or loss. Non-Hermitian topological systems exhibit many unique physical effects, the most famous of which is the non-Hermitian skin effect (where all bulk wave functions in the system are localized at the system's boundaries), which provides potential applications for non-reciprocal control and unidirectional amplification of signals.

[0004] like Figure 1 As shown, in order to achieve the non-Hermitian skin effect in circuit systems, related technologies typically rely on the explicit introduction of gain and loss elements (such as active elements or resistor networks) in each node or coupling of the circuit lattice.

[0005] However, solutions relying on complex active gain and loss components distributed throughout the system lead to problems such as complex circuit structures, high manufacturing costs, reduced system stability, and susceptibility to noise, hindering practical applications and expansion. Furthermore, explicit non-Hermitian designs struggle to achieve efficient control in wave-like systems (such as acoustics and optics). Summary of the Invention

[0006] This application provides a heterojunction unidirectional signal amplification topology circuit based on the Z2 skin effect to solve the problems of complex circuit structure, poor stability and susceptibility to noise interference caused by the introduction of additional gain or loss terms to realize non-Hermitian topology phenomena. It has the advantages of simple structure, high stability and low noise.

[0007] The first aspect of this application provides a heterojunction for a unidirectional signal amplification topology circuit based on the Z2 skin effect. The heterojunction is formed by connecting topologically non-trivial regions and topologically trivial regions at an interface. The nontrivial region of the topology is a two-dimensional square circuit lattice. In the two-dimensional square circuit lattice, each adjacent node is connected through a first coupling element or a second coupling element. Each node includes four circuit sub-units, and each circuit sub-unit is connected to a ground inductor or a ground capacitor. The topological trivial region is a rectangular circuit lattice, in which each adjacent node is connected by a third coupling element or a fourth coupling element. The boundary nodes of the non-trivial region of the topology are connected to the boundary nodes of the trivial region of the topology through a fifth coupling element.

[0008] Optionally, in some embodiments, in the two-dimensional square circuit lattice, The first circuit subunit in the cross node is connected to the first circuit subunit in the upward cross node, the second circuit subunit in the upward cross node, the first circuit subunit in the downward cross node, the first circuit subunit in the left cross node, the first circuit subunit in the right cross node, and the fourth circuit subunit in the right cross node via the first coupling element. The first circuit subunit in the cross node is connected to the second circuit subunit in the downward cross node and the fourth circuit subunit in the left cross node via the second coupling element. The second circuit subunit in the cross node is connected to the first circuit subunit in the upward cross node, the second circuit subunit in the upward cross node, the second circuit subunit in the downward cross node, the second circuit subunit in the left cross node, the third circuit subunit in the left cross node, and the second circuit subunit in the right cross node via the second coupling element. The second circuit subunit in the cross node is connected to the first circuit subunit in the downward cross node and the third circuit subunit in the right cross node via the first coupling element. The third circuit subunit in the cross node is connected to the third circuit subunit in the upward cross node, the fourth circuit subunit in the upward cross node, the third circuit subunit in the downward cross node, the second circuit subunit in the left cross node, the third circuit subunit in the left cross node, and the third circuit subunit in the right cross node via the first coupling element. The third circuit subunit in the cross node is connected to the second circuit subunit in the right cross node and the fourth circuit subunit in the downward cross node via the second coupling element. The fourth circuit subunit in the cross node is connected to the third circuit subunit in the upward cross node, the fourth circuit subunit in the upward cross node, the fourth circuit subunit in the downward cross node, the first circuit subunit in the left cross node, and the fourth circuit subunit in the right cross node via the second coupling element. The fourth circuit subunit in the cross node is connected to the first circuit subunit in the left cross node and the third circuit subunit in the downward cross node via the first coupling element.

[0009] Optionally, in some embodiments, in the two-dimensional square circuit lattice, The first circuit sub-unit in the cross node is connected to the grounding inductor; The second circuit subunit in the cross node is connected to the grounding capacitor. The third circuit subunit in the cross node is connected to the grounding inductor; The fourth circuit subunit in the cross node is connected to the grounding capacitor.

[0010] Optionally, in some embodiments, the first coupling element is a capacitor and the second coupling element is an inductor.

[0011] Optionally, in some embodiments, in the rectangular circuit lattice, adjacent nodes in each first direction are connected by the third coupling element, and adjacent nodes in each second direction are connected by the fourth coupling element.

[0012] Optionally, in some embodiments, the third coupling element is a capacitor and the fourth coupling element is an inductor.

[0013] Optionally, in some embodiments, the coupling strength between adjacent nodes of the topologically non-trivial region and the coupling strength between the boundary node of the topologically non-trivial region and the boundary node of the topologically trivial region satisfy a first preset relationship, wherein the first preset relationship is: ; in, The coupling strength between adjacent nodes in a topologically nontrivial region. The coupling strength between the boundary nodes of the non-trivial region of the topology and the boundary nodes of the trivial region of the topology.

[0014] Optionally, in some embodiments, the heterojunction described above includes: Adjust the coupling strength between adjacent nodes in the non-trivial region of the topology, the first self-admittance of the grounding inductor, and the first self-admittance of the grounding capacitor so that the zero level of the non-trivial region of the topology is located in the band gap.

[0015] Optionally, in some embodiments, the zero level of the rectangular circuit lattice in the topologically trivial region is located in the conduction band.

[0016] Optionally, in some embodiments, the boundary nodes of the topologically non-trivial region and the boundary nodes of the topologically trivial region are connected by a fifth coupling element, including: The first and third circuit sub-units in the boundary node of the non-trivial region of the topology are connected to the boundary node of the trivial region of the topology through the fifth coupling element, which is an inductor.

[0017] Therefore, the embodiments of this application have the following beneficial effects: (1) This application implicitly introduces non-Hermitian terms through energy exchange between topological non-trivial regions and topological trivial regions, transforms the topological boundary state into a non-Hermitian skin effect, realizes asymmetric transmission of signals along the heterojunction interface direction, does not require explicit gain or loss components, and the system has the advantages of simple structure, high stability and low noise.

[0018] (2) This application can be used for unidirectional signal amplification and can be extended to acoustic, optical and other wave systems, and has good application value.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0020] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram illustrating the principle of a scheme for implementing non-Hermitian topological phenomena in related technologies. Figure 2 This is a schematic diagram of a heterojunction of a unidirectional signal amplification topology circuit based on the Z2 skin effect according to an embodiment of this application; Figure 3 This is a schematic diagram of the circuit principle of a non-trivial region 11 in a topology according to an embodiment of this application; Figure 4 This is a schematic diagram of the voltage response curve when the right-handed mode is excited according to an embodiment of this application; Figure 5 This is a schematic diagram of the voltage response curve when a left-handed mode is excited according to an embodiment of this application; Figure 6 This is a schematic diagram of the excitation response curve after introducing circuit gain at the heterojunction interface according to an embodiment of this application. Detailed Implementation

[0021] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0022] The following description, with reference to the accompanying drawings, describes a heterojunction-based unidirectional signal amplification topology circuit of this application based on the Z2 skin effect. Addressing the problems mentioned in the background art, such as the complexity of circuit structure and susceptibility to noise interference caused by the introduction of additional gain or loss terms to achieve non-Hermitian topology phenomena, this application provides a heterojunction-based unidirectional signal amplification topology circuit based on the Z2 skin effect. The heterojunction is formed by connecting topologically nontrivial regions and topologically trivial regions at the interface. The topologically nontrivial region is a two-dimensional square circuit lattice, in which each adjacent node is connected through a first or second coupling element. Each node includes four circuit sub-units, and each circuit sub-unit is connected to a ground inductor or ground capacitor. The topologically trivial region is a rectangular circuit lattice, in which each adjacent node is connected through a third or fourth coupling element. The boundary nodes of the topologically nontrivial region and the boundary nodes of the topologically trivial region are connected through a fifth coupling element. This solves the problems of complex circuit structure, poor stability, and susceptibility to noise interference caused by the introduction of additional gain or loss terms to achieve non-Hermitian topology phenomena, and has the advantages of simple structure, high stability, and low noise.

[0023] Specifically, Figure 2 This is a schematic diagram of a heterojunction 1 of a unidirectional signal amplification topology circuit based on the Z2 skin effect, provided in an embodiment of this application.

[0024] like Figure 2 As shown, the heterojunction 1 of the unidirectional signal amplification topology circuit based on the Z2 skin effect is formed by connecting a topologically nontrivial region 11 and a topologically trivial region 12 at the interface. The topologically nontrivial region 11 is a two-dimensional square circuit lattice. In the two-dimensional square circuit lattice, each adjacent node is connected through a first coupling element 111 or a second coupling element 112. Each node includes four circuit sub-units, and each circuit sub-unit is connected to a ground inductor or a ground capacitor. The topologically trivial region 12 is a rectangular circuit lattice. In the rectangular circuit lattice, each adjacent node is connected through a third coupling element 121 or a fourth coupling element 122. The boundary node of the topologically nontrivial region 11 and the boundary node of the topologically trivial region 12 are connected through a fifth coupling element 13.

[0025] It should be noted that the Z2 topological invariant, used to describe the topological properties of the quantum spin Hall effect, is numerically equal to the remainder of the logarithm of the boundary states divided by two, and therefore can only take the value 0 or 1. When the value is 1, the system is topologically nontrivial, and there exists a pair of spiral boundary states with opposite propagation directions. The heterojunction structure transforms the spiral boundary states into a pair of skin modes with opposite directions through the self-energy interaction of the topologically trivial region 12, i.e., the Z2 skin effect.

[0026] Specifically, in this embodiment, the topologically nontrivial region 11 (equivalent to a square lattice topological insulator) and the topologically trivial region 12 (equivalent to a square lattice conductor) are connected at the interface to form a heterojunction. Through energy exchange between the topologically nontrivial region 11 and the topologically trivial region 12, a non-Hermitian term is implicitly introduced, converting the spiral topological boundary state into a Z2 non-Hermitian skin effect. This enables asymmetric signal transmission along the heterojunction interface direction (e.g., a left-handed signal is transmitted towards the - x Directional decay is faster, towards + x Directional transmission is enhanced (the opposite is true for right-handed signals), eliminating the need for active components such as operational amplifiers, resulting in a simple system structure, high stability, and low noise.

[0027] Further, in some embodiments, in a two-dimensional square circuit lattice, the first circuit sub-unit in the cross node is connected to the first circuit sub-unit in the upward cross node, the second circuit sub-unit in the upward cross node, the first circuit sub-unit in the downward cross node, the first circuit sub-unit in the left cross node, the first circuit sub-unit in the right cross node, and the fourth circuit sub-unit in the right cross node via a first coupling element 111. The first circuit sub-unit in the cross node is connected to the second circuit sub-unit in the downward cross node and the fourth circuit sub-unit in the left cross node via a second coupling element 112. The second circuit sub-unit in the cross node is connected to the first circuit sub-unit in the upward cross node, the second circuit sub-unit in the upward cross node, the second circuit sub-unit in the downward cross node, the second circuit sub-unit in the left cross node, the third circuit sub-unit in the left cross node, and the second circuit sub-unit in the right cross node via a second coupling element 112. The second circuit sub-unit in the cross node is connected to the first circuit sub-unit in the downward cross node and the third circuit sub-unit in the right cross node via a second coupling element 112. The circuit sub-units are connected to each other via a first coupling element 111; the third circuit sub-unit in the cross node is connected to the third circuit sub-unit in the upward cross node, the fourth circuit sub-unit in the upward cross node, the third circuit sub-unit in the downward cross node, the second circuit sub-unit in the left cross node, the third circuit sub-unit in the left cross node, and the third circuit sub-unit in the right cross node via a first coupling element 111; the third circuit sub-unit in the cross node is connected to the second circuit sub-unit in the right cross node and the fourth circuit sub-unit in the downward cross node via a second coupling element 112; the fourth circuit sub-unit in the cross node is connected to the third circuit sub-unit in the upward cross node, the fourth circuit sub-unit in the upward cross node, the fourth circuit sub-unit in the downward cross node, the first circuit sub-unit in the left cross node, and the fourth circuit sub-unit in the right cross node via a second coupling element 112; the fourth circuit sub-unit in the cross node is connected to the first circuit sub-unit in the left cross node and the third circuit sub-unit in the downward cross node via a first coupling element 111.

[0028] Furthermore, in some embodiments, in a two-dimensional square circuit lattice, the first circuit sub-unit in the cross node is connected to a ground inductor; the second circuit sub-unit in the cross node is connected to a ground capacitor; the third circuit sub-unit in the cross node is connected to a ground inductor; and the fourth circuit sub-unit in the cross node is connected to a ground capacitor.

[0029] Optionally, in some embodiments, the heterojunction 1 described above includes: adjusting the coupling strength between adjacent nodes of the topological nontrivial region 11, the first self-admittance of the ground inductance, and the first self-admittance of the ground capacitance, so that the zero level of the topological nontrivial region 11 is located in the band gap.

[0030] In this configuration, the first coupling element 111 is a capacitor, and the second coupling element 112 is an inductor.

[0031] Specifically, such as Figure 3 As shown, the topologically nontrivial region 11 is an equivalent square lattice formed by connecting circuit elements, simulating the Z2 topological insulator BHZ model proposed by Bernevig, Hughes, and Zhang in their study of the quantum spin Hall effect. The BHZ model describes an atomic system with a two-dimensional square lattice, where each atom has four independent electronic states. Correspondingly, the circuit simulating the BHZ model adopts a modular design, with each unit corresponding to one atom and four circuit nodes corresponding to the four electronic states within each unit. There is no connection between the four nodes within a unit, but the nodes of adjacent units are connected by capacitance or inductance (the admittance of the connecting element is defined as the coupling strength). In this configuration, the circuit admittance matrix will have the same mathematical form as the Hamiltonian matrix of the BHZ model, thus enabling the simulation of an atomic model using a circuit. Furthermore, each circuit node adjusts its self-admittance via a grounded inductor or capacitor, ensuring that its simulated Hamiltonian zero level lies within the bandgap. The circuit in this configuration supports spiral topological boundary states under open boundary conditions.

[0032] Optionally, in some embodiments, in a rectangular circuit lattice, adjacent nodes in each first direction are connected by a third coupling element 121, and adjacent nodes in each second direction are connected by a fourth coupling element 122.

[0033] Furthermore, in some embodiments, the zero level of the rectangular circuit lattice of the topological trivial region 12 is located in the conduction band.

[0034] Among them, the third coupling element 121 is a capacitor, the fourth coupling element 122 is an inductor, the first direction can be the horizontal direction, i.e. the X direction, and the second direction can be the vertical direction, i.e. the Y direction.

[0035] Specifically, the 12 circuit elements in the topological trivial region are connected to form an equivalent rectangular lattice to simulate a conductor. Adjacent nodes are connected in the x and y directions by capacitance or inductance (coupling strengths are respectively...). and The zero level of the topologically trivial region 12 is located in the conduction band, ensuring that it can exchange energy with the topologically nontrivial region 11.

[0036] Optionally, in some embodiments, the boundary nodes of the topological non-trivial region 11 and the boundary nodes of the topological trivial region 12 are connected by a fifth coupling element 13, including: the first circuit sub-unit and the third circuit sub-unit in the boundary node of the topological non-trivial region 11 are connected to the boundary node of the topological trivial region 12 by the fifth coupling element 13, wherein the fifth coupling element 13 is an inductor.

[0037] Specifically, the two circuit nodes in each cell on the boundary of the non-trivial region 11 are connected to the boundary node of the trivial region 12 via a capacitor or an inductor (coupling strength is...). The coupling strength between adjacent nodes of topologically nontrivial region 11 and the coupling strength between the boundary node of topologically nontrivial region 11 and the boundary node of topologically trivial region 12 satisfy a first preset relationship, wherein the first preset relationship is: ; in, Let be the coupling strength between adjacent nodes in the topologically nontrivial region 11. denoted as the coupling strength between the boundary nodes of topologically nontrivial region 11 and the boundary nodes of topologically trivial region 12.

[0038] After obtaining the heterojunction of the unidirectional signal amplification topology circuit based on the Z2 skin effect in the embodiments of this application, an excitation signal of equal amplitude is simultaneously applied to nodes A and C of the central unit, and the pulse phase at point A leads the pulse phase at point C by 90 degrees to excite the voltage response curve when the right-handed mode is activated, exhibiting asymmetric transmission characteristics, such as... Figure 4 As shown.

[0039] When an equal-amplitude excitation signal is simultaneously applied to nodes A and C of the central element, with the pulse phase at point A lagging 90 degrees behind that at point C to excite the left-handed mode, the voltage response curve exhibits the same characteristics as... Figure 4 Conversely, asymmetric transmission, such as Figure 5 As shown.

[0040] By introducing circuit gain into the excitation response curve on the interface, unidirectional signal amplification can be achieved. The right-hand rotary mode is input from the cell at coordinate 1, and the left-hand rotary mode is input from the cell at coordinate 9, as shown below. Figure 6 As shown.

[0041] In addition, embodiments of this application also provide a method for fabricating a heterojunction of a unidirectional signal amplification topology circuit based on the non-Hermitian skin effect, the method comprising the following steps: S1, using methods including but not limited to printed circuit boards, direct wire connections, etc., to connect the above-mentioned circuit lumped components that meet the parameter requirements according to... Figure 2 and Figure 3The connection relationships shown are processed into corresponding circuits for the topological insulator region 11 and the conductor region 12.

[0042] S2, using capacitors or inductors as connecting elements, connects the topological insulator region 11 and the conductor region 12 at the boundary. Figure 2 Connect them as shown to obtain the heterojunction 1 of the topology circuit.

[0043] According to the embodiments of this application, a heterojunction for unidirectional signal amplification topology circuit based on the Z2 skin effect is proposed. The heterojunction is formed by connecting topologically nontrivial regions and topologically trivial regions at the interface. The topologically nontrivial region is a two-dimensional square circuit lattice, in which each adjacent node is connected through a first or second coupling element. Each node includes four circuit sub-units, and each circuit sub-unit is connected to a ground inductor or ground capacitor. The topologically trivial region is a rectangular circuit lattice, in which each adjacent node is connected through a third or fourth coupling element. The boundary nodes of the topologically nontrivial region and the boundary nodes of the topologically trivial region are connected through a fifth coupling element. This solves the problems of complex circuit structure, poor stability, and susceptibility to noise interference caused by introducing additional gain or loss terms to realize non-Hermitian topology phenomena, and has the advantages of simple structure, high stability, and low noise.

[0044] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0046] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0047] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (FPGAs), field-programmable gate arrays (FPGAs), etc.

[0048] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0049] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A heterojunction of a unidirectional signal amplification topology circuit based on the Z2 skin effect, characterized in that, The heterojunction is formed by connecting topologically nontrivial regions and topologically trivial regions at the interface, wherein, The nontrivial region of the topology is a two-dimensional square circuit lattice. In the two-dimensional square circuit lattice, each adjacent node is connected through a first coupling element or a second coupling element. Each node includes four circuit sub-units, and each circuit sub-unit is connected to a ground inductor or a ground capacitor. The topological trivial region is a rectangular circuit lattice, in which each adjacent node is connected by a third coupling element or a fourth coupling element. The boundary nodes of the non-trivial region of the topology are connected to the boundary nodes of the trivial region of the topology through a fifth coupling element.

2. The heterojunction according to claim 1, characterized in that, In the two-dimensional square circuit lattice, The first circuit subunit in the cross node is connected to the first circuit subunit in the upward cross node, the second circuit subunit in the upward cross node, the first circuit subunit in the downward cross node, the first circuit subunit in the left cross node, the first circuit subunit in the right cross node, and the fourth circuit subunit in the right cross node via the first coupling element. The first circuit subunit in the cross node is connected to the second circuit subunit in the downward cross node and the fourth circuit subunit in the left cross node via the second coupling element. The second circuit subunit in the cross node is connected to the first circuit subunit in the upward cross node, the second circuit subunit in the upward cross node, the second circuit subunit in the downward cross node, the second circuit subunit in the left cross node, the third circuit subunit in the left cross node, and the second circuit subunit in the right cross node via the second coupling element. The second circuit subunit in the cross node is connected to the first circuit subunit in the downward cross node and the third circuit subunit in the right cross node via the first coupling element. The third circuit subunit in the cross node is connected to the third circuit subunit in the upward cross node, the fourth circuit subunit in the upward cross node, the third circuit subunit in the downward cross node, the second circuit subunit in the left cross node, the third circuit subunit in the left cross node, and the third circuit subunit in the right cross node via the first coupling element. The third circuit subunit in the cross node is connected to the second circuit subunit in the right cross node and the fourth circuit subunit in the downward cross node via the second coupling element. The fourth circuit subunit in the cross node is connected to the third circuit subunit in the upward cross node, the fourth circuit subunit in the upward cross node, the fourth circuit subunit in the downward cross node, the first circuit subunit in the left cross node, and the fourth circuit subunit in the right cross node via the second coupling element. The fourth circuit subunit in the cross node is connected to the first circuit subunit in the left cross node and the third circuit subunit in the downward cross node via the first coupling element.

3. The heterojunction according to claim 2, characterized in that, In the two-dimensional square circuit lattice, The first circuit sub-unit in the cross node is connected to the grounding inductor; The second circuit subunit in the cross node is connected to the grounding capacitor. The third circuit subunit in the cross node is connected to the grounding inductor; The fourth circuit subunit in the cross node is connected to the grounding capacitor.

4. The heterojunction according to claim 2, characterized in that, The first coupling element is a capacitor, and the second coupling element is an inductor.

5. The heterojunction according to claim 1, characterized in that, In the rectangular circuit lattice, adjacent nodes in each first direction are connected by the third coupling element, and adjacent nodes in each second direction are connected by the fourth coupling element.

6. The heterojunction according to claim 5, characterized in that, The third coupling element is a capacitor, and the fourth coupling element is an inductor.

7. The heterojunction according to claim 1, characterized in that, The coupling strength between adjacent nodes of the topologically nontrivial region and the coupling strength between the boundary node of the topologically nontrivial region and the boundary node of the topologically trivial region satisfy a first preset relationship, wherein the first preset relationship is: ； in, The coupling strength between adjacent nodes in a topologically nontrivial region. The coupling strength between the boundary nodes of the non-trivial region of the topology and the boundary nodes of the trivial region of the topology.

8. The heterojunction according to claim 1, characterized in that, include: Adjust the coupling strength between adjacent nodes in the non-trivial region of the topology, the first self-admittance of the grounding inductor, and the first self-admittance of the grounding capacitor so that the zero level of the non-trivial region of the topology is located in the band gap.

9. The heterojunction according to claim 1, characterized in that, The zero level of the rectangular circuit lattice in the topologically trivial region is located in the conduction band.

10. The heterojunction according to claim 1, characterized in that, The boundary nodes of the topologically non-trivial region and the boundary nodes of the topologically trivial region are connected by a fifth coupling element, including: The first and third circuit sub-units in the boundary node of the non-trivial region of the topology are connected to the boundary node of the trivial region of the topology through the fifth coupling element, which is an inductor.

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