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Preparation method of topological insulator structure

一种拓扑绝缘体、反应腔体的技术，应用在拓扑绝缘体结构的制备领域，能够解决未制造出、尚未制造出拓扑绝缘体等问题，达到大反常霍尔电阻、实现量子化反常霍尔效应、降低载流子浓度的效果

Active Publication Date: 2013-03-27
TSINGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, a topological insulator capable of quantizing the anomalous Hall effect has not actually been fabricated
Even a ferromagnetic material (including magnetically doped topological insulator )

Method used

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  • Preparation method of topological insulator structure
  • Preparation method of topological insulator structure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0069] Example 1 (T=30mK, 5QL sample, back gate control)

[0070] The magnetic doped topological insulator quantum well film is Cr 0.15 (Bi 0.10 Sb 0.9 ) 1.85 Te 3 , the thickness is 5QL, and the insulating substrate 30 is an STO substrate.

[0071] The Hall curves of the topological insulator structure under different back gate voltages were measured. see Figure 6-9 , at a temperature of 30 milliKelvin (mK), the R of the sample AH With the back gate voltage (V b ) changes with changes. Figure 6-9 Hysteresis also appears in the middle Hall curve, and the sample has very good ferromagnetism. When 0V≤V b ≤10V, the R of the sample AH With V b The change is small when V b at -4.5V, R AH is 25.8 kΩ. where μ 0 H in H is the magnetization, and μ 0 is the vacuum magnetic permeability, and the unit T is Tesla.

Embodiment 2

[0072] Example 2 (T=1.5K, 4QL sample, back gate regulation)

[0073] The magnetic doped topological insulator quantum well film is Cr 0.22 (Bi 0.22 Sb 0.78 ) 1.78 Te 3 , the thickness is 4QL, and the insulating substrate 30 is an STO substrate.

[0074] see Figure 10 , at T=1.5K, 4QL Cr on STO(111) substrate 0.22 (Bi 0.22 Sb 0.78 ) 1.78 Te 3 different V b The Hall curve under Figure 10 shown. from Figure 10 It can be seen that the Hall curve has hysteresis, and the shape of the hysteresis loop is very "square", indicating that the sample has very good ferromagnetism. by V b regulation, can obtain higher R AH . R AH With V b The increase first increases and then decreases, when V b =45V, R AH It reaches the maximum, about 10 kΩ, which is close to 0.4 quantum resistance (25.8kΩ). Figure 11 is the sample at different V b under the reluctance curve for different V b Below, the magnetoresistance curves are all "butterfly-shaped", which also shows that t...

Embodiment 3

[0075] Example 3 (T=100mK, 4QL sample, back gate regulation)

[0076] The magnetic doped topological insulator quantum well film is Cr 0.22 (Bi 0.22 Sb 0.78 ) 1.78 Te 3 , the thickness is 4QL, and the insulating substrate 30 is an STO substrate.

[0077] The Hall curves of the topological insulator structure under different back gate voltages were measured. see Figure 13 , at a temperature of 100 milliKelvin (mK), the R of the sample AH With the back gate voltage (V b ) changes with changes. Figure 13 Hysteresis also appears in the middle Hall curve, and the sample has very good ferromagnetism. When 0V≤V b ≤20V, the R of the sample AH With V b little change in R AH Close to 0.6 quantum resistance (25.8kΩ). Specifically, when V b =10 V, R AH max, (R AH ) max =0.59h?e -2 , that is about 15.3kΩ. This value has far exceeded half of the quantum Hall resistance value, and is the largest abnormal Hall resistance that can be obtained in the world so far. Fi...

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Abstract

The invention relates to a preparation method of a topological insulator structure, which comprises the following steps of: providing a strontium titanate substrate; performing thermal treatment on the strontium titanate substrate in a molecular beam epitaxial reaction cavity so that the surface is clean; heating the strontium titanate substrate and forming beams of Bi, Sb, Cr and Te in the molecular beam epitaxial reaction cavity at the same time; and controlling the flow of the beams of Bi, Sb, Cr and Te to control the proportion of Bi, Sb, Cr to Te so that a hole-type carrier introduced into a magnetic doping topological insulator quantum well film and an electronic type carrier introduced into the magnetic doping topological insulator quantum well film basically cancel out each other, thus a magnetic doping topological insulator quantum well film is formed on the surface of the strontium titanate substrate, wherein the material of the magnetic doping topological insulator quantum well film is expressed by a chemical formula Cry(BixSb1-x)(2-y)Te3, 0<x<1, 0<y<2, and the thickness of the magnetic doping topological insulator quantum well film is 3-5QL.

Description

technical field [0001] The invention belongs to the field of condensed matter physics and relates to a preparation method of a topological insulator structure. Background technique [0002] The Hall effect (HE) was discovered by American physicist E. H. Hall in 1879 while studying the conductive structure of metals. When the current passes through the conductor perpendicular to the external magnetic field, a potential difference will appear between the two end faces of the conductor perpendicular to the direction of the magnetic field and current. This phenomenon is the Hall effect. Scientists subsequently discovered the anomalous Hall effect (AHE) in magnetic materials and the spin Hall effect (SHE) in semiconductors. Theoretically, the three Hall effects should exist in their corresponding quantized forms under certain conditions. In 1980, German physicist K. V. Klitzing discovered the quantum Hall effect (quantum Hall effect, QHE) (Klitzing K. V. et al., New Method for...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B25/02C30B25/18C30B29/46H01L43/14
CPCC30B25/186C30B23/025C30B23/002H10N52/01H10N50/85
Inventor 薛其坤何珂马旭村陈曦王立莉常翠祖冯硝李耀义贾金锋
Owner TSINGHUA UNIV
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