Stripe charge order and its interaction with Majorana bound states in 2M-WS2 topological superconductors

Xuemin Fan; Xiao-Qi Sun; Penghao Zhu; Yuqiang Fang; Yongkang Ju; Yonghao Yuan; Jingming Yan; Fuqiang Huang; Taylor L Hughes; Peizhe Tang; Qi-Kun Xue; Wei Li

doi:10.1093/nsr/nwae312

Stripe charge order and its interaction with Majorana bound states in 2M-WS₂ topological superconductors

Natl Sci Rev. 2024 Sep 5;12(2):nwae312. doi: 10.1093/nsr/nwae312. eCollection 2025 Feb.

Authors

Xuemin Fan^{1

2

3}, Xiao-Qi Sun⁴, Penghao Zhu⁴, Yuqiang Fang^{5

6}, Yongkang Ju⁷, Yonghao Yuan^{1

2

3}, Jingming Yan^{1

2

3}, Fuqiang Huang^{5

6}, Taylor L Hughes⁴, Peizhe Tang^{7

8}, Qi-Kun Xue^{1

2

3

9

10}, Wei Li^{1

2

3}

Affiliations

¹ State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
² Frontier Science Center for Quantum Information, Beijing 100084, China.
³ Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
⁴ Institute for Condensed Matter Physics and Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
⁵ State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China.
⁶ State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
⁷ School of Materials Science and Engineering, Beihang University, Beijing 100191, China.
⁸ Max Planck Institute for the Structure and Dynamics of Matter, Center for Free-Electron Laser Science, Hamburg 22761, Germany.
⁹ Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
¹⁰ Southern University of Science and Technology, Shenzhen 518055, China.

Abstract

To achieve logic operations via Majorana braiding, positional control of the Majorana bound states (MBSs) must be established. Here we report the observation of a striped surface charge order coexisting with superconductivity and its interaction with the MBS in the topological superconductor 2M-WS₂, using low-temperature scanning tunneling microscopy. By applying an out-of-plane magnetic field, we observe that MBSs are absent in vortices in the region with stripe order. This is in contrast to adjacent underlaying layers without charge order, where vortex-bound MBSs are observed. Via theoretical simulations, we show that the surface stripe order does not destroy the bulk topology, but it can effectively modify the spatial distribution of MBSs, i.e. it pushes them downward, away from the 2M-WS₂ surface. Our findings demonstrate that the interplay of charge order and topological superconductivity can potentially be used to tune the positions of MBSs, and to explore new states of matter.

Keywords: 2M-WS2; Majorana bound states; stripe charge order; topological superconductor.