Exciton fine structure splitting and linearly polarized emission in strained transition-metal dichalcogenide monolayers

M. M. Glazov, Florian Dirnberger, Vinod M. Menon, Takashi Taniguchi, Kenji Watanabe, Dominique Bougeard, Jonas D. Ziegler, and Alexey Chernikov

Phys. Rev. B 106, 125303 – Published 13 September 2022

Abstract

We study theoretically the effects of an anisotropic elastic strain on the exciton energy spectrum fine structure and optical selection rules in atomically thin crystals based on transition-metal dichalcogenides. The presence of strain breaks the chiral selection rules at the $K$ points of the Brillouin zone and makes optical transitions linearly polarized. The orientation of the induced linear polarization is related to the main axes of the strain tensor. Elastic strain provides an additive contribution to the exciton fine structure splitting, in agreement with experimental evidence obtained from the uniaxially strained ${WSe}_{2}$ monolayer. The applied strain also induces momentum-dependent Zeeman splitting. Depending on the strain orientation and magnitude, Dirac points with a linear dispersion can be formed in the exciton energy spectrum. We provide a symmetry analysis of the strain effects and develop a microscopic theory for all relevant strain-induced contributions to the exciton fine structure Hamiltonian.

Received 28 June 2022
Revised 29 August 2022
Accepted 30 August 2022

DOI:https://doi.org/10.1103/PhysRevB.106.125303

Physics Subject Headings (PhySH)

Exchange interaction Excitons Spin polarization Strain

Two-dimensional electron system Van der Waals systems

Perturbation theory Photoluminescence Strain engineering

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

M. M. Glazov

Ioffe Institute, 194021 Saint Petersburg, Russia and National Research University, Higher School of Economics, 190121 Saint Petersburg, Russia

Florian Dirnberger

Department of Physics, City College of New York, New York, New York 10031, USA; Department of Physics, The Graduate Center, City University of New York, New York, New York 10016, USA; and Integrated Center for Applied Physics and Photonic Materials, Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany

Vinod M. Menon

Department of Physics, City College of New York, New York, New York 10031, USA and Department of Physics, The Graduate Center, City University of New York, New York, New York 10016, USA

Takashi Taniguchi

International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan

Kenji Watanabe

Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan

Dominique Bougeard

Department of Physics, University of Regensburg, 93040 Regensburg, Germany

Jonas D. Ziegler and Alexey Chernikov

Integrated Center for Applied Physics and Photonic Materials, Institute of Applied Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany

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Issue

Vol. 106, Iss. 12 — 15 September 2022

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