Giant valley splitting in monolayer WS2 by magnetic proximity effect

Tenzin Norden, Chuan Zhao, Peiyao Zhang, Renat Sabirianov, Athos Petrou, Hao Zeng

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Lifting the valley degeneracy of monolayer transition metal dichalcogenides (TMDs) would allow versatile control of the valley degree of freedom. We report a giant valley exciton splitting of 16 meV/T for monolayer WS2, using the proximity effect from an EuS substrate, which is enhanced by nearly two orders of magnitude from that obtained by an external magnetic field. More interestingly, a sign reversal of the valley splitting is observed as compared to that of WSe2 on EuS. Using first principles calculations, we investigate the complex behavior of exchange interactions between TMDs and EuS. The sign reversal is attributed to competing ferromagnetic (FM) and antiferromagnetic (AFM) exchange interactions for Eu- and S- terminated EuS surface sites. They act differently on the conduction and valence bands of WS2 compared to WSe2. Tuning the sign and magnitude of the valley exciton splitting offers opportunities for control of valley pseudospin for quantum information processing.

Original languageEnglish (US)
Article number4163
JournalNature communications
Volume10
Issue number1
DOIs
StatePublished - Dec 1 2019

Fingerprint

Exchange interactions
Transition metals
valleys
Monolayers
Metals
Magnetic Fields
Valence bands
Conduction bands
Automatic Data Processing
Tuning
Magnetic fields
Substrates
transition metals
excitons
LDS 751
conduction bands
degrees of freedom
tuning
interactions
valence

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

Cite this

Giant valley splitting in monolayer WS2 by magnetic proximity effect. / Norden, Tenzin; Zhao, Chuan; Zhang, Peiyao; Sabirianov, Renat; Petrou, Athos; Zeng, Hao.

In: Nature communications, Vol. 10, No. 1, 4163, 01.12.2019.

Research output: Contribution to journalArticle

Norden, Tenzin ; Zhao, Chuan ; Zhang, Peiyao ; Sabirianov, Renat ; Petrou, Athos ; Zeng, Hao. / Giant valley splitting in monolayer WS2 by magnetic proximity effect. In: Nature communications. 2019 ; Vol. 10, No. 1.
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