美国阿贡国家实验室材料科学部门Anand Bhattacharya发现了KTaO3（111）界面的二维超导电性和输运各向异性。相关研究成果发表在2021年出版的《科学》。

在材料之间的界面上发现的独特的电子结构可以让非传统的量子态出现。

该文文报道了在（111）取向的KTaO3与EuO或LaAlO3的绝缘覆盖层之间形成的电子气体中发现的超导性。超导转变温度接近2.2k，比LaAlO3/SrTiO3体系高一个数量级。

引人注目的是，KTaO3（001）界面上类似的电子气体在25mK下仍保持正常。临界场和电流电压测量表明超导电性是二维的。在EuO/KTaO3（111）样品中，在超导电性开始之前，观察到了自发的面内输运各向异性，这表明在临界场附近出现了明显的条带相。

附：英文原文

Title: Two-dimensional superconductivity and anisotropic transport at KTaO3 (111) interfaces

Author: Changjiang Liu, Xi Yan, Dafei Jin, Yang Ma, Haw-Wen Hsiao, Yulin Lin, Terence M. Bretz-Sullivan, Xianjing Zhou, John Pearson, Brandon Fisher, J. Samuel Jiang, Wei Han, Jian-Min Zuo, Jianguo Wen, Dillon D. Fong, Jirong Sun, Hua Zhou, Anand Bhattacharya

Issue&Volume: 2021/01/21

Abstract: The unique electronic structure found at interfaces between materials can allow unconventional quantum states to emerge. Here we report on the discovery of superconductivity in electron gases formed at interfaces between (111) oriented KTaO3 and insulating overlayers of either EuO or LaAlO3. The superconducting transition temperature, approaching 2.2 K, is about one order of magnitude higher than that of the LaAlO3/SrTiO3 system. Strikingly, similar electron gases at KTaO3 (001) interfaces remain normal down to 25 mK. The critical field and current-voltage measurements indicate that the superconductivity is two dimensional. In EuO/KTaO3 (111) samples, a spontaneous in-plane transport anisotropy is observed prior to the onset of superconductivity, suggesting the emergence of a distinct ‘stripe’ like phase, which is also revealed near the critical field.

DOI: 10.1126/science.aba5511

Source: https://science.sciencemag.org/content/early/2021/01/21/science.aba5511