Title: Topological vortex bound states in superconducting topological materials

报告人：秦盛山 博士（中国科学院卡弗里理论科学研究所）

时间：2022年4月日29 10:00-12:00

地点：沙河校区C827会议室；腾讯会议：497-213-837

Abstract:
The topological states of matter have been one of the most active research fields in condensed matter physics. An intriguing property of the topological materials is that, in the superconducting state they may host the long-pursuit Majorana modes, which are expected to play an essential role in the fault-tolerant quantum computations. One of the most famous proposal is the Fu-Kane formula, where Majorana zero-energy modes are proposed to exist in the superconducting vortices if the conventional superconductivity is introduced into the surface Dirac cone of a topological insulator by proximity effect. However, except for the topological insulators, whether the superconducting vortices can bound the Majorana modes in other topological materials, such as the topological semimetals, is still unknown. In this talk, I will introduce our series of works on the vortex bound states in the superconducting topological materials. First, I will introduce the concept of topological vortex phase transition, and provide an understanding for the Fu-Kane formula from a different perspective. Then, I will show that the Majorana modes are ubiquitous in the vortices in the superconducting topological materials, and different kinds of Majorana modes can exist in the different topological systems, including the topological insulators, the topological Dirac and Weyl semimetals. The related experimental progress, especially in the iron-based superconductors in recent years, will also be presented.

References:
P. Hosur, et al., Majorana Modes at the Ends of Superconductor Vortices in Doped Topological Insulators, Phys. Rev. Lett. 107, 097001 (2011).
Shengshan Qin, et al., Quasi-1D topological nodal vortex line phase in doped superconducting 3D Dirac Semimetals, Phys. Rev. Lett. 123, 027003 (2019).
Shengshan Qin, et al., Topological Vortex Phase Transitions in Iron-Based Superconductors, Sci. Bull. 64, 1207 (2019).
Yi Zhang*, Shengshan Qin*, et al., Gapless vortex bound states in superconducting topological semimetals, arXiv:2102.06494.
Shengshan Qin, et al., Topological Phase Transitions of Superconducting Vortex Bound States Driven by Impurities, arXiv:2010.09382.

About the Speaker:
Dr. Shengshan Qin obtained his bachelor’s degree from Wuhan University in 2011, and received the PhD degree in condensed matter theory from the institute of physics, Chinese Academy of Sciences in 2018. Then he works as postdoc in Kavli institute for theoretical sciences, University of Chinese Academy of Sciences till now. He mainly works in the fields of unconventional superconductivity and topological states of matter.

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联系人：刘老师 010-61716757 ruiliu@buaa.edu.cn