Year: 2015
Type: article
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 -0.22 meV/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.
Source: Physical Review Letters
Institutions: Cornell University, University of Konstanz, Lancaster University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, McGill University, Eidgenössische Technische Hochschule Zürich, Cornell Center for Materials Research, Materials Research Science and Engineering Center, Harvard University, Kavli Institute at Cornell, Cornell University, Natural Sciences and Engineering Research Council of Canada, Division of Materials Research, Division of Electrical, Communications and Cyber Systems
OpenAlex ID: W2044480396