Intrinsic Valley-Polarized Quantum Anomalous Hall Effect and Controllable Topological Phase Transition in Janus Fe2SSe

Hongxin Chen; Ran Liu; Jiajun Lu; Xiuwen Zhao; Guichao Hu; Junfeng Ren; Xiaobo Yuan

doi:10.1021/acs.jpclett.2c02794

Intrinsic Valley-Polarized Quantum Anomalous Hall Effect and Controllable Topological Phase Transition in Janus Fe₂SSe

J Phys Chem Lett. 2022 Nov 10;13(44):10297-10304. doi: 10.1021/acs.jpclett.2c02794. Epub 2022 Oct 28.

Authors

Hongxin Chen¹, Ran Liu¹, Jiajun Lu¹, Xiuwen Zhao¹, Guichao Hu¹, Junfeng Ren^{1

2}, Xiaobo Yuan¹

Affiliations

¹ School of Physics and Electronics, Shandong Normal University, Jinan250358, China.
² Shandong Provincial Engineering and Technical Center of Light Manipulations & Institute of Materials and Clean Energy, Shandong Normal University, Jinan250358, China.

PMID: 36305806
DOI: 10.1021/acs.jpclett.2c02794

Abstract

The valley-polarized quantum anomalous Hall effect (VP-QAHE) in topological materials, which usually is induced by applying external manipulations, has attracted intensive attention. Here, we predict the formation and regulation of the intrinsic VP-QAHE in ferromagnetic Janus monolayer Fe₂SSe. Spontaneous valley polarization (VP) appears without external manipulations due to the Janus structure in monolayer Fe₂SSe. The spontaneous VP in addition to the nonzero Chern number in Fe₂SSe confirm the intrinsic VP-QAHE. Besides, the topologically protected chiral-spin-valley locking edge states can be regulated by reversing the magnetization. Topological phase transitions between metal, half-metal, topological insulator, and ferrovalley phases can be obtained by applying biaxial strains in Fe₂SSe, and the nontrivial band gap reaches up to 441 meV. Also, the topological phase with the VP-QAHE is robust under certain conditions. Both the intrinsic VP-QAHE and controllable topological phase transitions can be achieved in Janus monolayer Fe₂SSe, which provides an avenue for the applications of dissipationless valleytronic devices.