Discovery of tip induced unconventional superconductivity on Weyl semimetal

He Wang; Huichao Wang; Yuqin Chen; Jiawei Luo; Zhujun Yuan; Jun Liu; Yong Wang; Shuang Jia; Xiong-Jun Liu; Jian Wei; Jian Wang

doi:10.1016/j.scib.2017.02.009

Discovery of tip induced unconventional superconductivity on Weyl semimetal

Sci Bull (Beijing). 2017 Mar 30;62(6):425-430. doi: 10.1016/j.scib.2017.02.009. Epub 2017 Feb 24.

Authors

He Wang¹, Huichao Wang¹, Yuqin Chen¹, Jiawei Luo¹, Zhujun Yuan¹, Jun Liu², Yong Wang², Shuang Jia¹, Xiong-Jun Liu³, Jian Wei⁴, Jian Wang⁵

Affiliations

¹ International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing, China.
² Center of Electron Microscopy, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
³ International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing, China. Electronic address: [email protected].
⁴ International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing, China. Electronic address: [email protected].
⁵ International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing, China. Electronic address: [email protected].

PMID: 36659286
DOI: 10.1016/j.scib.2017.02.009

Abstract

Weyl fermion is a massless Dirac fermion with definite chirality, which has been long pursued since 1929. Though it has not been observed as a fundamental particle in nature, Weyl fermion can be realized as low-energy excitation around Weyl point in Weyl semimetal, which possesses Weyl fermion cones in the bulk and nontrivial Fermi arc states on the surface. As a firstly discovered Weyl semimetal, TaAs crystal possesses 12 pairs of Weyl points in the momentum space, which are topologically protected against small perturbations. Here, we report for the first time the tip induced superconductivity on TaAs crystal by point contact spectroscopy. The zero bias conductance peak as well as a conductance plateau with double conductance peaks and sharp double dips are observed in the point contact spectra simultaneously, indicating unconventional superconductivity. Our further theoretical study suggests that the induced superconductivity may have nontrivial topology. The present work opens a new route in investigating the novel superconducting states based on Weyl materials.

Keywords: Point contact spectroscopy; TaAs; Tip induced unconventional superconductivity; Topological superconductivity; Weyl semimetal.