Breaking of valley degeneracy by magnetic field in monolayer MoSe2

David Macneill, Colin Heikes, Kin Fai Mak, Zachary Anderson, Andor Kormányos, Viktor Zólyomi, Jiwoong Park, Daniel C. Ralph

Research output: Contribution to journalArticlepeer-review

357 Scopus citations

Abstract

Using polarization-resolved photoluminescence spectroscopy, we investigate the breaking of valley degeneracy by an out-of-plane magnetic field in back-gated monolayer MoSe2 devices. We observe a linear splitting of -0.22meV/T between luminescence peak energies in σ+ and σ- emission for both neutral and charged excitons. The optical selection rules of monolayer MoSe2 couple the photon handedness to the exciton valley degree of freedom; so this splitting demonstrates valley degeneracy breaking. In addition, we find that the luminescence handedness can be controlled with a magnetic field to a degree that depends on the back-gate voltage. An applied magnetic field, therefore, provides effective strategies for control over the valley degree of freedom.

Original languageEnglish (US)
Article number037401
JournalPhysical review letters
Volume114
Issue number3
DOIs
StatePublished - Jan 22 2015

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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