Tsinghua University

Chinese Academy of Sciences

Jin-Feng Jia

Xi Chen

Ke He

Qi-Kun Xue

Li-Li Wang

Xu-Cun Ma

Xiao Feng

Cui-Zu Chang

Yao-Yi Li

Zhi Hong Li

Shuai-Hua Ji

Wen-Hao Zhang

Qing-Yan Wang

A high-temperature superconducting film includes a SrTiOsubstrate, a single crystalline FeSe layer, and a protective layer with a layered crystal structure. The single crystalline FeSe layer is sandwiched between the SrTiOsubstrate and the protective layer via a layer-by-layer mode. An onset temperature of superconducting transition of the high-temperature superconducting film is greater than or equal to 54 K, and a critical current density of the high-temperature superconducting film is about 10A/cmat 12 K.

High-temperature superconducting film

A method for making a high-temperature superconducting film includes loading a SrTiOsubstrate in an ultra-high vacuum system. A single crystalline FeSe layer is grown on a surface of the SrTiOsubstrate by molecular beam epitaxy. A protective layer with a layered crystal structure is grown by molecular beam epitaxy and covering the single crystalline FeSe layer.

Method for making high-temperature superconducting film

A method for forming a topological insulator structure is provided. A strontium titanate substrate having a surface (111) is used. The surface (111) of the strontium titanate substrate is cleaned by heat-treating the strontium titanate substrate in the molecular beam epitaxy chamber. The strontium titanate substrate is heated and Bi beam, Sb beam, Cr beam, and Te beam are formed in the molecular beam epitaxy chamber in a controlled ratio achieved by controlling flow rates of the Bi beam, Sb beam, Cr beam, and Te beam. The magnetically doped topological insulator quantum well film is formed on the surface (111) of the strontium titanate substrate. The amount of the hole type charge carriers introduced by the doping with Cr is substantially equal to the amount of the electron type charge carriers introduced by the doping with Bi.

Method for making topological insulator structure

A topological insulator structure includes an insulating substrate and a magnetically doped TI quantum well film located on the insulating substrate. A material of the magnetically doped TI quantum well film is represented by a chemical formula of Cr(BiSb)Te. 0.05&#x3c;x&#x3c;0.3, 0&#x3c;y&#x3c;0.3, and 1:2&#x3c;x:y&#x3c;2:1. The magnetically doped TI quantum well film is in 3 QL to 5 QL.

Electrical device having magnetically doped topological insulator quantum well film

A topological insulator structure includes an insulating substrate and a magnetically doped TI quantum well film located on the insulating substrate. A material of the magnetically doped TI quantum well film is represented by a chemical formula of Cr(BiSb)Te. 0&#x3c;x&#x3c;1, 0&#x3c;y&#x3c;2. Values of x and y satisfies that an amount of a hole type charge carriers introduced by a doping with Cr is substantially equal to an amount of an electron type charge carriers introduced by a doping with Bi. The magnetically doped TI quantum well film is in 3 QL to 5 QL.

Topological insulator structure having magnetically doped topological insulator quantum well film

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Beijing, China

Jin-Feng Jia