High- T c superconductor Fe(Se,Te) monolayer: an intrinsic, scalable and electrically tunable Majorana platform

Xianxin Wu; Xin Liu; Ronny Thomale; Chao-Xing Liu

doi:10.1093/nsr/nwab087

High- T _c superconductor Fe(Se,Te) monolayer: an intrinsic, scalable and electrically tunable Majorana platform

Natl Sci Rev. 2021 May 19;9(3):nwab087. doi: 10.1093/nsr/nwab087. eCollection 2022 Mar.

Authors

Xianxin Wu¹, Xin Liu², Ronny Thomale¹, Chao-Xing Liu³

Affiliations

¹ Institut für Theoretische Physik und Astrophysik, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany.
² School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
³ Department of Physics, the Pennsylvania State University, University Park, PA 16802, USA.

Abstract

Iron-based superconductors have been identified as a novel platform for realizing Majorana zero modes (MZMs) without heterostructures, due to their intrinsic topological properties and high-T _c superconductivity. In the two-dimensional limit, the FeTe_1-x Se _x monolayer, a topological band inversion has recently been experimentally observed. Here, we propose to create MZMs by applying an in-plane magnetic field to the FeTe_1-x Se _x monolayer and tuning the local chemical potential via electric gating. Owing to the anisotropic magnetic couplings on edges, an in-plane magnetic field drives the system into an intrinsic high-order topological superconductor phase with Majorana corner modes. Furthermore, MZMs can occur at the domain wall of chemical potentials at either one edge or certain type of tri-junction in the two-dimensional bulk. Our study not only reveals the FeTe_1-x Se _x monolayer as a promising Majorana platform with scalability and electrical tunability and within reach of contemporary experimental capability, but also provides a general principle to search for realistic realization of high-order topological superconductivity.

Keywords: Majorana zero modes; high-order topological superconductivity; iron-based superconductors.