Termination-dependent Superconducting Topological Surface States in Non-centrosymmetric PbTaSe2
Syu-You Guan1,2*, Peng-Jen Chen1,2,3, Ming-Wen Chu4, Raman Sankar2,4, Fangcheng Chou4, Horng-Tay Jeng2,5, Chia-Seng Chang1,2, Tien-Ming Chuang2
1Department of Physics, National Taiwan University, Taipei, Taiwan
2Institute of Physics, Academia Sinica, Taipei, Taiwan
3Nano Science and Technology Program, TIGP, Academia Sinica, Taipei, Taiwan
4Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
5Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
* Presenter:Syu-You Guan, email:r95222038@gmail.com
The search for topological superconductors (TSCs) is one of the most exciting subjects in condensed matter physics. TSCs are characterized by a full superconducting gap in the bulk and topologically protected gapless surface or edge states. Within each vortex core of TSCs, there exist the zero energy Majorana bound states. So far, PbTaSe2 is the only stoichiometric bulk material exhibits the required topological surface states at EF combined with fully gapped bulk superconductivity1. Interestingly, two distinct and stable terminations have been identified to be Pb- and Se-surface by using spectroscopic imaging-scanning tunneling microscope. Two terminations exhibit striking difference in both atomic and electronic structure above Tc while both exhibit a full superconducting gap and zero energy bound state in the superconducting vortex core2. Our results show PbTaSe2 is a great platform for the study of 2D TSC.

Keywords: STM, Topological surface state, Superconductor