Topological vortex phase transitions in iron-based superconductors

Shengshan Qin; Lunhui Hu; Xianxin Wu; Xia Dai; Chen Fang; Fu-Chun Zhang; Jiangping Hu

doi:10.1016/j.scib.2019.07.011

Topological vortex phase transitions in iron-based superconductors

Sci Bull (Beijing). 2019 Sep 15;64(17):1207-1214. doi: 10.1016/j.scib.2019.07.011. Epub 2019 Jul 15.

Authors

Shengshan Qin¹, Lunhui Hu², Xianxin Wu³, Xia Dai⁴, Chen Fang⁵, Fu-Chun Zhang⁶, Jiangping Hu⁷

Affiliations

¹ Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Beijing National Research Center for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
² Department of Physics, University of California, San Diego, CA 92093, USA; Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
³ Institute for Theoretical Physics and Astrophysics, Julius-Maximilians University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
⁴ Beijing National Research Center for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
⁵ Beijing National Research Center for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China.
⁶ Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: fuchun@ucas.ac.cn.
⁷ Beijing National Research Center for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100049, China; Collaborative Innovation Center of Quantum Matter, Beijing 100049, China. Electronic address: jphu@iphy.ac.cn.

PMID: 36659600
DOI: 10.1016/j.scib.2019.07.011

Abstract

We study topological vortex phases in iron-based superconductors. Besides the previously known vortex end Majorana zero modes (MZMs) phase stemming from the existence of a three dimensional (3D) strong topological insulator state, we show that there is another topologically nontrivial phase as iron-based superconductors can be doped superconducting 3D weak topological insulators (WTIs). The vortex bound states in a superconducting 3D WTI exhibit two different types of quantum states, a robust nodal superconducting phase with pairs of bulk MZMs and a full-gap topologically nontrivial superconducting phase which has single vortex end MZM in a certain range of doping level. Moreover, we predict and summarize various topological phases in iron-based superconductors, and find that carrier doping and interlayer coupling can drive systems to have phase transitions between these different topological phases.

Keywords: Iron-based superconductors; Majorana modes; Vortex bound states; Weak topological insulators.