Large valley splitting in monolayer WS 2 by proximity coupling to an insulating antiferromagnetic substrate

Lei Xu, Ming Yang, Lei Shen, Jun Zhou, Tao Zhu, Yuan Ping Feng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

96 Citations (Scopus)

Abstract

Lifting the valley degeneracy is an efficient way to achieve valley polarization for further valleytronics operations. In this Rapid Communication, we demonstrate that a large valley splitting can be obtained in monolayer transition metal dichalcogenides by magnetic proximity coupling to an insulating antiferromagnetic substrate. As an example, we perform first-principles calculations to investigate the electronic structures of monolayer WS2 on the MnO(111) surface. Our calculation results suggest that a large valley splitting of 214 meV, which corresponds to a Zeeman magnetic field of 1516 T, is induced in the valence band of monolayer WS2. The magnitude of valley splitting relies on the strength of interfacial orbital hybridization and can be tuned continually by applying an external out-of-plane pressure and in-plane strain. More interestingly, we find that both spin and valley index will flip when the magnetic ordering of MnO is reversed. Besides, owing to the sizable Berry curvature and time-reversal symmetry breaking in the WS2/MnO heterostructure, a spin- and valley-polarized anomalous Hall current can be generated in the presence of an in-plane electric field, which allows one to detect valleys by the electrical approach. Our results shed light on the realization of valleytronic devices using the antiferromagnetic insulator as the substrate.

Original languageEnglish
Article number041405
JournalPhysical Review B
Volume97
Issue number4
DOIs
Publication statusPublished - 10 Jan 2018

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint

Dive into the research topics of 'Large valley splitting in monolayer WS 2 by proximity coupling to an insulating antiferromagnetic substrate'. Together they form a unique fingerprint.

Cite this