Discovery of tip induced unconventional superconductivity on Weyl semimetal  

作　　者：He Wang Huichao Wang Yuqin Chen Jiawei Luo Zhujun Yuan Jun Liu Yong Wang Shuang Jia Xiong-Jun Liu jian Wei Jian Wang 

机构地区：[1]International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China [2]Collaborative Innovation Center of Quantum Matter, Beijing, China [3]Center of Electron Microscopy, State Key Laboratory of Silicon Materials, School of Materials Sdence and Engineering, Zhejiang University, Hangzhou 310027, China

出　　处：《Science Bulletin》2017年第6期425-430,共6页科学通报（英文版）

基　　金：financially supported by National Basic Research Program of China (2013CB934600,2012CB927400,2012CB921300,and 2016YFA0301604);the Research Fund for the Doctoral Program of Higher Education (RFDP) of China;the Open Project Program of the Pulsed High Magnetic Field Facility (PHMFF2015002);Huazhong University of Science and Technology,Open Research Fund Program of the State Key Laboratory of Low Dimensional Quantum Physics;the National Natural Science Foundation of China (11474008 and 11574008)

摘　　要：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,Ta As 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 Ta As 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.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 crys- tal 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 simultane- ously, indicating unconventional superconductivity. Our further theoretical study suggests that the induced superconductivity may have nontrivial topology. The present work opens a new route in inves- tigating the novel superconducting states based on Wey1 materials.

关 键 词：Tip induced unconventional SUPERCONDUCTIVITY Topological superconductivity Weyl semimetal TAAS Point contact spectroscopy 

分 类 号：O511.3[一般工业技术—材料科学与工程]