论文标题
尖端引起的超导性
Tip-induced Superconductivity
论文作者
论文摘要
人们普遍认为,可以通过诱导拓扑材料中的超导性来实现拓扑超导性,这是一种迄今难以捉摸的量子物质阶段。为了寻找这种拓扑超导体,某些拓扑绝缘子(例如Bi $ _2 $ se $ _3 $)成功地转变为Metal-Ion(Cu,PD,SR,NB等)的超导体。也可以通过施加压力在拓扑材料中诱导超导性。例如,在拓扑绝缘子BI $ _2 $ SE $ _3 $中发现了压力引起的超导阶段。但是,在所有这种情况下,尚未发现拓扑超导性的结论性特征。在这篇综述中,我们将讨论另一种新颖的方式,即通过在材料上创建一种具有非抑制,正常金属尖端的介质界面,诱导非抑制性拓扑材料中的超导性,其中介观界面成为超导。现在,这种阶段被称为尖端诱导的超导(TISC)阶段。这是在2014年首次在印度Iiser Mohali的CD $ _3 $上出现的。随后,显示了许多其他拓扑材料显示tisc。由于tisc阶段仅在介观点接触下出现在受限区域,因此无法使用表征超导性的传统散装工具来检测/确认此类阶段。另一方面,这样的点接触几何形状是探测温度和磁场的可能存在依赖性超导能量隙以及温度和磁场依赖临界电流的理想选择。我们将回顾可用于证明超导性存在的实验签名的细节,即使无法执行检测超导性的“教科书”测试。然后,我们将审查可以实现TISC阶段的不同系统。
It is widely believed that topological superconductivity, a hitherto elusive phase of quantum matter, can be achieved by inducing superconductivity in topological materials. In search of such topological superconductors, certain topological insulators (like, Bi$_2$Se$_3$) were successfully turned into superconductors by metal-ion (Cu, Pd, Sr, Nb etc. ) intercalation. Superconductivity could be induced in topological materials through applying pressure as well. for example, a pressure-induced superconducting phase was found in the topological insulator Bi$_2$Se$_3$. However, in all such cases, no conclusive signature of topological superconductivity was found. In this review, we will discuss about another novel way of inducing superconductivity in a non-superconducting topological material -- by creating a mesoscopic interface on the material with a non-superconducting, normal metallic tip where the mesoscopic interface becomes superconducting. Such a phase is now known as a tip-induced superconducting (TISC) phase. This was first seen in 2014 on Cd$_3$As$_2$ at IISER Mohali, India. Following that, a large number of other topological materials were shown to display TISC. Since the TISC phase emerges only at a confined region under a mesoscopic point contact, traditional bulk tools for characterizing superconductivity cannot be employed to detect/confirm such a phase. On the other hand, such a point contact geometry is ideal for probing the possible existence of a temperature and magnetic field dependent superconducting energy gap and a temperature and magnetic field dependent critical current. We will review the details of the experimental signatures that can be used to prove the existence of superconductivity even when the "text-book" tests for detecting superconductivity cannot be performed. Then, we will review different systems where a TISC phase could be realized.