Tip-induced or enhanced superconductivity: a way to detect topological superconductivity

He Wang; Lei Ma; Jian Wang

doi:10.1016/j.scib.2018.07.019

Tip-induced or enhanced superconductivity: a way to detect topological superconductivity

Sci Bull (Beijing). 2018 Sep 15;63(17):1141-1158. doi: 10.1016/j.scib.2018.07.019. Epub 2018 Jul 29.

Authors

He Wang¹, Lei Ma², Jian Wang³

Affiliations

¹ Tianjin International Center for Nano Particles and Nano Systems, Tianjin University, Tianjin 300072, China; International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
² Tianjin International Center for Nano Particles and Nano Systems, Tianjin University, Tianjin 300072, China. Electronic address: maleixinjiang@tju.edu.cn.
³ International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China; State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China. Electronic address: jianwangphysics@pku.edu.cn.

PMID: 36658994
DOI: 10.1016/j.scib.2018.07.019

Abstract

Topological materials, hosting topological nontrivial electronic band, have attracted widespread attentions. As an application of topology in physics, the discovery and study of topological materials not only enrich the existing theoretical framework of physics, but also provide fertile ground for investigations on low energy excitations, such as Weyl fermions and Majorana fermions, which have not been observed yet as fundamental particles. These quasiparticles with exotic physical properties make topological materials the cutting edge of scientific research and a new favorite of high tech. As a typical example, Majorana fermions, predicted to exist in the edge state of topological superconductors, are proposed to implement topological error-tolerant quantum computers. Thus, the detection of topological superconductivity has become a frontier in condensed matter physics and materials science. Here, we review a way to detect topological superconductivity triggered by the hard point contact: tip-induced superconductivity (TISC) and tip-enhanced superconductivity (TESC). The TISC refers to the superconductivity induced by a non-superconducting tip at the point contact on non-superconducting materials. We take the elaboration of the chief experimental achievement of TISC in topological Dirac semimetal Cd₃As₂ and Weyl semimetal TaAs as key components of this article for detecting topological superconductivity. Moreover, we also briefly introduce the main results of another exotic effect, TESC, in superconducting Au₂Pb and Sr₂RuO₄ single crystals, which are respectively proposed as the candidates of helical topological superconductor and chiral topological superconductor. Related results and the potential mechanism are conducive to improving the comprehension of how to induce and enhance the topological superconductivity.

Keywords: Point contact spectroscopy; Tip-enhanced superconductivity; Tip-induced superconductivity; Topological materials; Topological superconductivity.

Publication types

Review