Construction method of two-dimensional atomic lattice with topological angular state

Abstract

The invention discloses a two-dimensional atomic lattice construction method with a topological angular state, and the method comprises the steps: depositing metal atoms on the surface of an III-V group semiconductor substrate with a symmetrical vacancy surface structure, and enabling the metal atoms to be ionized and anchored through the vacancy of the surface of the substrate; the method comprises the following steps: acquiring surface topography data of a semiconductor by using a scanning tunneling microscope and a needle point thereof, carrying metal ions on the surface of an III-V group semiconductor substrate one by one, accurately controlling the distance between the metal ions, and forming single artificial quantum dots; constructing n artificial quantum dots in the same way, and forming a two-dimensional atomic lattice on the surface of the semiconductor substrate; adjusting the lattice point spacing of the two-dimensional atomic lattice, regulating and controlling t / r, removing or adding artificial quantum dots by using a needle tip, designing a boundary structure at the edge of the two-dimensional array, and constructing the two-dimensional atomic lattice with a topological angular state. According to the invention, controllable construction of the topological angular state and accurate regulation and control of lattice topological properties are realized, and a new research platform is provided for solid-state quantum calculation.

Description

Technical Field

[0001] The present invention belongs to the field of atomic-level manufacturing and relates to a method for constructing a two-dimensional atomic lattice with topological corner states. Background Art

[0002] As a unique research platform, two-dimensional atomic lattices provide an important way for people to explore the application of various novel quantum effects in quantum devices. The controllable filling of the flat bands at the Fermi level position of two-dimensional atomic lattices can achieve artificial ferromagnetic order, and the second-order topological corner states at their boundaries can be used as topologically protected qubits, thus having important application prospects in the field of solid-state quantum computing.

[0003] In recent years, researchers have synthesized and grown actual materials with two-dimensional atomic lattice structures, such as CoSn, FeSn, and AV3Sb5 family compounds, and found two-dimensional kagome lattices composed of metal atoms in these actual materials. They provide ideal models for studying novel material states such as flat-band physics and topological phases. The AV3Sb5 family compounds with kagome lattice structures have attracted extensive attention because they have been confirmed to have unconventional superconductivity and simultaneously exhibit topological surface states. In addition, a flat-band electronic structure near the Fermi level has been observed in the paramagnetic kagome lattice material CoSn, and the anomalous anisotropy of transport and magnetism caused by flat-band electrons has been revealed, successfully revealing the macroscopic electronic behavior caused by flat bands. However, due to the difficulty in changing and regulating structural elements such as lattice point units, lattice constants, symmetries, and boundary structures of the lattice systems synthesized and grown in actual materials, two-dimensional atomic lattices with special physical properties, namely, breathing kagome lattices and square lattices, are difficult to achieve in actual materials, and it is more difficult to regulate their lattice physical properties.

[0004] In view of this, the present invention proposes a method for constructing a two-dimensional atomic lattice with topological corner states to solve the above problems. Summary of the Invention

[0005] To solve the above-mentioned defects in the prior art, the purpose of the present invention is to provide a method for constructing a two-dimensional atomic lattice with topological corner states, which realizes the atomic-level precise construction of a two-dimensional atomic lattice by constructing artificial quantum dots, and precisely adjusts the lattice parameters and physical properties of the two-dimensional atomic lattice by adjusting the spacing between artificial quantum dots.

[0006] The present invention is realized by the following technical solutions.

[0007] One aspect of the present invention provides a method for constructing a two-dimensional atomic lattice with topological corner states, including:

[0008] Select a III-V group semiconductor substrate with a symmetric vacancy surface structure and clean the substrate;

[0009] Deposit metal atoms on the surface of a group III-V semiconductor substrate. The vacancies on the surface of the semiconductor substrate ionize the metal atoms and anchor them at the vacancies.

[0010] Use a scanning tunneling microscope and its tip to collect the topographic data of the semiconductor surface and determine the positions of the metal ions bound to the symmetric vacancies on the substrate surface.

[0011] Use the tip to individually transport metal ions on the surface of the group III-V semiconductor substrate, and precisely control the spacing between the metal ions by adjusting the bias voltage and tunneling current, arranging them into a specific structure composed of multiple metal ions to form a single artificial quantum dot.

[0012] Move the scanning tunneling microscope tip near the first artificial quantum dot. The tip continues to transport metal ions and constructs the second, third,..., the nth artificial quantum dot in the same way, forming a two-dimensional atomic lattice with long-range order on the semiconductor substrate surface with the artificial quantum dots as lattice points.

[0013] Use the tip to adjust the lattice point spacing of the two-dimensional atomic lattice to achieve the regulation of the lattice parameters t / r.

[0014] Use the tip to remove or add artificial quantum dots, design a boundary structure at the edge of the two-dimensional array, and construct a two-dimensional atomic lattice with topological corner states.

[0015] Preferably, the selected group III-V semiconductor substrate includes GaAs and InAs.

[0016] Preferably, the selected group III-V semiconductor substrate with a symmetric vacancy surface structure has a specific crystal plane orientation, with regularly arranged vacancies on its surface and the vacancies showing symmetry, including the (111)A surface and the (110) surface.

[0017] Preferably, the metal atoms deposited on the surface of the group III-V semiconductor substrate ionize on the substrate surface to form metal ions, including Li+, Na+, K+, Rb+, Cs+ or In+.

[0018] Preferably, use the tip to individually transport metal ions on the surface of the group III-V semiconductor substrate, with the bias voltage range of -1.2 to +1.0 V and the tunneling current range of 5 to 8 nA.

[0019] Preferably, the single artificial quantum dot is composed of 4 or 6 metal ions and stably exists in a symmetric structure of a square or a regular hexagon.

[0020] Preferably, the lattice point spacing of the two-dimensional atomic lattice is 1.8 to 3.6 nm.

[0021] Preferably, the lattice parameter t / r is regulated, where t is the nearest-neighbor hopping integral between lattice points inside the unit, r is the nearest-neighbor hopping integral between lattice points of adjacent unit cells, and the lattice parameter t / r is used to measure the coupling strength between quantum dots; the lattice point spacing is 5.4 - 10.8 nm.

[0022] Preferably, the two-dimensional lattice is constructed under a low-temperature environment not exceeding 4.5 K and an ultra-high vacuum environment of 10 -8 Pa.

[0023] On the other hand, the present invention provides a two-dimensional atomic lattice with topological corner states constructed by the above method.

[0024] Due to the above technical solutions adopted by the present invention, it has the following beneficial effects:

[0025] The present invention uses the scanning tunneling microscope longitudinal manipulation technology to manipulate metal ions, realizes the construction of artificial quantum dots, and designs and constructs a two-dimensional atomic lattice with artificial quantum dots as lattice point units, breaking through the traditional method of artificially synthesizing two-dimensional atomic lattices in actual materials.

[0026] The lattice point unit of the two-dimensional atomic lattice described in the present invention is essentially electrons bound by a potential barrier formed by 4 - 6 charged cations on a III-V semiconductor substrate. By precisely adjusting the lattice parameters of the two-dimensional atomic lattice, the regulation of the lattice topological properties can be realized, and topological corner states can be achieved by designing the boundary structure of the two-dimensional lattice, providing a new research platform for solid-state quantum computing. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and do not constitute an improper limitation to the present invention. In the drawings:

[0028] Figure 1 (a)-(d) are schematic process flow diagrams for constructing artificial quantum dots;

[0029] Figure 2 is a schematic diagram of the principle of electrons bound by an artificial quantum dot composed of 6 metal ions on a III-V semiconductor substrate.

[0030] Figure 3 (a)-(f) are scanning tunneling microscope flowcharts for forming a primitive cell of a breathing kagome lattice on the InAs(111)A surface in Example 1; + is a scanning tunneling microscope flowchart for forming a primitive cell of a breathing kagome lattice on the InAs(111)A surface in Example 1;

[0031] Figure 4 (a) is a schematic diagram of a kagome lattice formed with artificial quantum dots as lattice point units on the InAs(111)A surface in Example 1;

[0032] Figure 4 (b)-(c) are enlarged views of kagome lattices formed by using artificial quantum dots formed by 6 In atoms on the InAs(111)A surface in Example 1; + The artificial quantum dots formed are the enlarged views of kagome lattices formed with lattice units;

[0033] Figure 5 (a)-(b) are schematic diagrams of breathing kagome lattices formed by adjusting the spacing of artificial quantum dots on the InAs(111)A surface in Example 1;

[0034] Figure 6 (a)-(f) are the scanning tunneling microscopy flowcharts of artificial quantum dots formed by 6 In atoms on the InAs(111)A surface in Example 1; + The artificial quantum dots formed are the scanning tunneling microscopy flowcharts;

[0035] Figure 7 (a)-(b) are schematic diagrams of square lattices formed by using artificial quantum dots as lattice units on a III-V semiconductor substrate in Example 2. Detailed implementation manners

[0036] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Here, the illustrative embodiments of the present invention and the descriptions are used to explain the present invention, but do not limit the present invention.

[0037] An embodiment of the present invention provides a method for constructing a two-dimensional atomic lattice with topological corner states, including the following steps:

[0038] Step 1: Select a III-V semiconductor substrate with a symmetric vacancy surface structure, including GaAs(111)A, GaAs(110), InAs(111)A, and InAs(110) surfaces.

[0039] Step 2: Deposit metal atoms on the surface of the selected III-V semiconductor substrate. The metal atoms are ionized on the substrate surface and anchored at the vacancies, as shown in Figure 1 (a) and (b).

[0040] Step 3: Use a scanning tunneling microscope and its tip to collect the surface topography data of the semiconductor, and determine the positions of metal ions combined with the symmetric vacancies on the substrate surface.

[0041] Use a scanning tunneling microscope and its tip to construct a two-dimensional lattice with atomic precision. The tip is prepared by electrochemical etching and cleaned by electron beam heating and neon ion sputtering.

[0042] Step 4: Use the tip to individually transport metal ions including Li+, Na+, K+, Rb+, Cs+, or In+ onto the surface of the III-V semiconductor substrate, and precisely control the spacing between metal ions by adjusting the bias voltage and tunneling current. Arrange them into a square or regular hexagon structure composed of 4 or 6 metal ions to form a single artificial quantum dot composed of 4 or 6 metal ions, as Figure 1 shown in (c). The bias voltage range for the tip to transport metal ions is -1.2 to +1.0 V, and the tunneling current range is 5 to 8 nA. The spacing range between metal ions within the quantum dot is 1.8 to 3.6 nm.

[0043] Step 5: Move the scanning tunneling microscope tip near the first quantum dot, and the tip continues to transport metal ions and construct the second quantum dot in the same manner, as Figure 1 shown in (d). The spacing between the two quantum dots is 5.4 to 10.8 nm. Adjusting the spacing d between the two quantum dots can change the potential well depth V of the bound electrons, as Figure 2 shown.

[0044] Step 6: Continue to move the tip, transport metal ions, and construct multiple artificial quantum dots to form a two-dimensional lattice with long-range order on the semiconductor substrate surface, with artificial quantum dots as lattice points. The two-dimensional lattice includes kagome lattice, breathing kagome lattice, and square lattice.

[0045] Step 7: Use the tip to precisely adjust the lattice point spacing of the two-dimensional atomic lattice to achieve the regulation of the lattice parameters t / r, that is, change the quantum dot coupling strength by adjusting the lattice point spacing to realize topological edge states in the two-dimensional lattice. The lattice point spacing adjustment range is 5.4 to 10.8 nm.

[0046] Step 8: Use the tip to remove or add artificial quantum dots and design boundary structures at the edge of the finite two-dimensional lattice, including zigzag boundaries and chain-like boundary structures, to achieve the construction of a two-dimensional atomic lattice with topological corner states.

[0047] In the present invention, the presence of surface reconstruction or dangling bonds on the III-V semiconductor substrate results in a large fluctuation in the potential energy surface and a high diffusion barrier, allowing metal ions to stably exist. The metal ions and the surface of the III-V semiconductor substrate belong to physical adsorption and are easily directionally transported by the tip. A single metal ion on the surface of the III-V semiconductor substrate will induce a local potential well at the adsorption site to trap electrons. With artificial quantum dots as lattice points, a two-dimensional lattice with long-range order is formed, including kagome lattice, breathing kagome lattice, and square lattice. The topological property of the two-dimensional lattice refers to the existence of topologically protected local corner states at the corners of the lattice. The two-dimensional atomic lattice is a finite lattice, and the design of its lattice boundary structure can be achieved by removing or adding quantum dots.

[0048] The present invention will be further illustrated by different embodiments below.

[0049] Example 1

[0050] The specific construction steps of the kagome lattice are as follows:

[0051] (1) Select a group III-V semiconductor InAs substrate material.

[0052] (2) Deposit an InAs layer on the (111)A surface of the substrate by thermal evaporation, and anneal it in an ultra-high vacuum environment to desorb the As overlay, obtaining the InAs(111)A surface. There are low-concentration In adsorbed atoms at the vacancy sites on the surface of the substrate after thermal evaporation, which will ionize on the InAs(111)A surface to form In + .

[0053] (3) Use a scanning tunneling microscope and its tip to scan the InAs(111)A surface to obtain the position distribution of In combined with the symmetric vacancies on the substrate surface. + Position distribution.

[0054] (4) Use the tip to individually transport In on the InAs(111)A surface, control the In + spacing within 2.0 nm, arrange it into a regular hexagon structure composed of 6 In + , and form a single artificial quantum dot composed of 6 In + , as shown in + (a)-(f). The bias voltage range for the tip to transport In Figure 3 is -1.2 V, and the tunneling current range is 6 nA. +

[0055] (5) Move the scanning tunneling microscope tip to 8.6 nm from the first quantum dot, and the tip continues to transport In + and construct the second quantum dot composed of 6 In + in the same way.

[0056] (6) Continue to move the tip, transport In + , construct multiple regular hexagon quantum dots, and form a kagome lattice with artificial quantum dots as lattice points and long-range order on the InAs(111)A surface, as shown in Figure 4 (a)-(c).

[0057] (7) Use the scanning tunneling microscope tip to precisely adjust the lattice point spacing of the two-dimensional lattice within 5.4 - 10.8 nm to achieve the regulation of t / r, that is, change the quantum dot coupling strength by adjusting the lattice point spacing to make the kagome lattice exhibit topological properties and form a breathing kagome lattice, as shown in Figure 5 (a)-(b) and Figure 6 (a)-(f).

[0058] (8) Form a zigzag boundary by removing or adding artificial quantum dots at the tip of the kagome lattice edge, and realize a breathing kagome lattice with topological corner states.

[0059] Example 2

[0060] The specific construction steps of the square lattice are as follows:

[0061] (1) Select a III-V semiconductor GaAs substrate material.

[0062] (2) Deposit Li on the (110) surface of the substrate by thermal evaporation. + , and ionization occurs on the GaAs(110) surface to form Li + .

[0063] (3) Use a scanning tunneling microscope and its tip to scan the GaAs(110) surface to obtain the position distribution of Li combined with symmetric vacancies on the substrate surface. + Position distribution.

[0064] (4) Use the tip to individually transport Li on the GaAs(110) surface. + , and control the Li + spacing within 3.6 nm, and arrange it into a hexagonal structure composed of 4 Li + to form a single artificial quantum dot composed of 4 Li + . The bias voltage range for the tip to transport Li + is -0.1 V, and the tunneling current range is 5 nA.

[0065] (5) Move the scanning tunneling microscope tip to 6.3 nm from the first quantum dot, and the tip continues to transport Li + and construct the second quantum dot composed of 4 Li + in the same way.

[0066] (6) Continue to move the tip to transport Li + , construct multiple quantum dots in the shape of a regular quadrilateral, and form a square lattice with long-range order on the GaAs(110) surface with artificial quantum dots as lattice points.

[0067] (7) Use the scanning tunneling microscope tip to precisely adjust the lattice point spacing of the two-dimensional lattice within 5.4 - 10.8 nm to regulate t / r, that is, change the quantum dot coupling strength by adjusting the lattice point spacing, so that the square lattice exhibits topological properties, forming a square lattice, as shown in Figure 7 (a)-(b).

[0068] (8) Form a chain-like boundary by removing or adding artificial quantum dots at the tip of the square lattice edge, and realize a square lattice with topological corner states.

[0069] Example 3

[0070] The specific construction steps of the kagome lattice are as follows:

[0071] (1) Select the III-V semiconductor GaAs substrate material.

[0072] (2) Deposit a GaAs layer on the surface of the substrate GaAs(111)A by thermal evaporation, and anneal it in an ultra-high vacuum environment to desorb the As overlay, obtaining the GaAs(111)A surface. There are low-concentration Ga adsorbed atoms at the vacant sites on the surface of the substrate after thermal evaporation, and they will ionize on the GaAs(111)A surface to form K+.

[0073] (3) Use a scanning tunneling microscope and its tip to scan the GaAs(111)A surface to obtain the position distribution of K+ combined with the symmetric vacant sites on the substrate surface.

[0074] (4) Use the tip to individually transport K+ on the GaAs(111)A surface, and control the distance between K+ within 1.8 nm, arranging them into a regular hexagon structure composed of 6 K+, forming a single artificial quantum dot composed of 6 K+. The bias voltage range for the tip to transport K+ is +1.0 V, and the tunneling current range is 7 nA.

[0075] (5) Move the scanning tunneling microscope tip to 5.4 nm from the first quantum dot, and the tip continues to transport K+ and constructs the second quantum dot composed of 6 K+ in the same way.

[0076] (6) Continue to move the tip, transport K+, and construct multiple regular hexagon quantum dots, forming a kagome lattice with artificial quantum dots as lattice points and long-range order on the GaAs(111)A surface.

[0077] (7) Use the scanning tunneling microscope tip to precisely adjust the lattice point spacing of the two-dimensional lattice within 5.4 - 10.8 nm to achieve the regulation of t / r, that is, change the quantum dot coupling strength by adjusting the lattice point spacing, so that the kagome lattice exhibits topological properties, forming a breathing kagome lattice.

[0078] (8) Use the tip at the edge of the kagome lattice to remove or add artificial quantum dots to form a zigzag boundary, realizing a breathing kagome lattice with topological corner states.

[0079] Example 4

[0080] The specific construction steps of the square lattice are as follows:

[0081] (1) Select the III-V semiconductor InAs substrate material.

[0082] (2) Deposit In⁺ on the surface of the substrate (110) by thermal evaporation, and ionization occurs on the surface of InAs (110) to form In⁺.

[0083] (3) Use a scanning tunneling microscope and its tip to scan the surface of InAs (110) to obtain the position distribution of In⁺ combined with symmetric vacancies on the substrate surface.

[0084] (4) Use the tip to individually transport In⁺ on the surface of InAs (110), control the distance between In⁺ within 2.6 nm, arrange them into a hexagonal structure composed of 4 In⁺, and form a single artificial quantum dot composed of 4 In⁺. The bias voltage range for the tip to transport In⁺ is +0.5 V, and the tunneling current range is 8 nA.

[0085] (5) Move the scanning tunneling microscope tip to 10.8 nm from the first quantum dot, and the tip continues to transport In⁺ and constructs the second quantum dot composed of 4 In⁺ in the same way.

[0086] (6) Continue to move the tip, transport In⁺, and construct multiple quantum dots in the shape of a square, forming a square lattice with artificial quantum dots as lattice points and long-range order on the surface of InAs (110).

[0087] (7) Use the scanning tunneling microscope tip to precisely adjust the lattice point spacing of the two-dimensional lattice within 5.4 - 10.8 nm to achieve the regulation of t / r, that is, change the quantum dot coupling strength by adjusting the lattice point spacing, so that the square lattice exhibits topological properties and forms a square lattice.

[0088] (8) Use the tip at the edge of the kagome lattice to remove or add artificial quantum dots to form a chain-like boundary, and achieve a square lattice with topological corner states.

[0089] This scheme realizes the construction of topological corner states by precisely regulating the lattice point spacing and boundary structure, providing a new method for studying new topological quantum devices and realizing high-fault-tolerant quantum computing.

[0090] The present invention is not limited to the above embodiments. Based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and deformations of some technical features without creative labor according to the disclosed technical content, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A method for constructing a two-dimensional atomic lattice with topological corner states, characterized in that, Including: Select a III-V semiconductor substrate with a symmetric vacancy surface structure and clean the substrate; Deposit metal atoms on the surface of the III-V semiconductor substrate. The vacancies on the surface of the semiconductor substrate ionize the metal atoms and anchor them at the vacancies; Use a scanning tunneling microscope and its tip to collect the surface topography data of the semiconductor to determine the positions of the metal ions bound to the symmetric vacancies on the substrate surface; Use the tip to transport metal ions one by one on the surface of the III-V semiconductor substrate, and precisely control the distance between metal ions by adjusting the bias voltage and tunneling current, and arrange them into a closed structure composed of multiple metal ions to form a single artificial quantum dot; Move the scanning tunneling microscope tip near the first artificial quantum dot. The tip continues to transport metal ions and constructs the second, third,... the nth artificial quantum dot in the same way to form a two-dimensional atomic lattice with long-range order on the semiconductor substrate surface with artificial quantum dots as lattice points; Use the tip to adjust the lattice point spacing of the two-dimensional atomic lattice, and by regulating t / r, realize the topological boundary state of the two-dimensional atomic lattice; Use the tip to remove or add artificial quantum dots, design a boundary structure at the edge of the two-dimensional array, and construct a two-dimensional atomic lattice with topological corner states.

2. The method for constructing a two-dimensional atomic lattice with topological corner states according to claim 1, characterized in that, The selected III-V semiconductor substrate includes GaAs and InAs.

3. A method for constructing a two-dimensional atomic lattice with topological corner states according to claim 1, characterized in that The selected III-V semiconductor substrate with a symmetric vacancy surface structure has a specific crystal plane orientation, with regularly arranged vacancies on its surface and the vacancies showing symmetry, including the (111)A surface and the (110) surface.

4. A method for constructing a two-dimensional atomic lattice with topological corner states according to claim 1, characterized in that, The metal atoms deposited on the surface of the III-V semiconductor substrate ionize on the substrate surface to form metal ions, including Li+, Na+, K+, Rb+, Cs+ or In+.

5. A method for constructing a two-dimensional atomic lattice with topological corner states according to claim 1, characterized in that, Use the tip to transport metal ions one by one on the surface of the III-V semiconductor substrate, with the bias voltage range of -1.2 to +1.0 V and the tunneling current range of 5 to 8 nA.

6. The method for constructing a two-dimensional atomic lattice with topological corner states according to claim 1, wherein The single artificial quantum dot is composed of 4 or 6 metal ions and stably exists in a symmetric structure of a square or a regular hexagon.

7. A method for constructing a two-dimensional atomic lattice with topological corner states according to claim 1, characterized in that, The lattice point spacing of the two-dimensional atomic lattice is 1.8 to 3.6 nm.

8. A method for constructing a two-dimensional atomic lattice with topological corner states according to claim 1, characterized in that The regulation of t / r, where t is the nearest-neighbor hopping integral between lattice points inside the unit, r is the nearest-neighbor hopping integral between lattice points of adjacent unit cells, and t / r is used to measure the coupling strength between quantum dots; the lattice point spacing is 5.4 to 10.8 nm.

9. A method for constructing a two-dimensional atomic lattice with topological corner states according to claim 1, characterized in that, The two-dimensional lattice is constructed under a cryogenic environment not exceeding 4.5 K and an ultra-high vacuum environment of 10 -8 Pa.

10. A two-dimensional atomic lattice with topological corner states constructed by the method according to any one of claims 1-9.

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