Ren Tianshuang, Li Miaocong, Sun Xikang, Ju Lele, Liu Yuan, Hong Siyuan, Sun Yanqiu, Tao Qian, Zhou Yi, Xu Zhu-An, Xie Yanwu
Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, and Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, China.
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Sci Adv. 2022 Jun 3;8(22):eabn4273. doi: 10.1126/sciadv.abn4273.
The recent discovery of superconductivity at the interfaces between KTaO and EuO (or LaAlO) gives birth to the second generation of oxide interface superconductors. This superconductivity exhibits a strong dependence on the surface plane of KTaO, in contrast to the seminal LaAlO/SrTiO interface, and the superconducting transition temperature is enhanced by one order of magnitude. For understanding its nature, a crucial issue arises: Is the formation of oxide interfaces indispensable for the occurrence of superconductivity? Exploiting ionic liquid (IL) gating, we are successful in achieving superconductivity at KTaO(111) and KTaO(110) surfaces with up to 2.0 and 1.0 K, respectively. This oxide-IL interface superconductivity provides a clear evidence that the essential physics of KTaO interface superconductivity lies in the KTaO surfaces doped with electrons. Moreover, the controllability with IL technique paves the way for studying the intrinsic superconductivity in KTaO.
最近在KTaO与EuO（或LaAlO）界面处发现的超导现象催生了第二代氧化物界面超导体。与开创性的LaAlO/SrTiO界面不同，这种超导现象对KTaO的表面平面表现出强烈的依赖性，并且超导转变温度提高了一个数量级。为了理解其本质，出现了一个关键问题：氧化物界面的形成对于超导现象的发生是否不可或缺？利用离子液体（IL）门控技术，我们成功地在KTaO(111)和KTaO(110)表面分别实现了高达2.0 K和1.0 K的超导现象。这种氧化物-离子液体界面超导现象提供了明确的证据，表明KTaO界面超导现象的基本物理原理在于掺杂电子的KTaO表面。此外，离子液体技术的可控性为研究KTaO中的本征超导现象铺平了道路。
