Strain tunable interlayer and intralayer excitons in vertically stacked MoSe2/WSe2 heterobilayers

Li LL, Gillen R, Palummo M, Milošević MV, Peeters FM (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Applied Physics Letters American Institute of Physics (AIP)

Book Volume: 123

Article Number: 033102

Journal Issue: 3

DOI: 10.1063/5.0147761

Abstract

Recently, interlayer and intralayer excitons in transition metal dichalcogenide heterobilayers have been studied both experimentally and theoretically. In spite of a growing interest, these layer-resolved excitons in the presence of external stimuli, such as strain, remain not fully understood. Here, using density-functional theory calculations with many-body effects, we explore the excitonic properties of vertically stacked MoSe2/WSe2 heterobilayer in the presence of in-plane biaxial strain of up to 5%. We calculate the strain dependence of exciton absorption spectrum, oscillator strength, wave function, and binding energy by solving the Bethe-Salpeter equation on top of the standard GW approach. We identify the interlayer and intralayer excitons by analyzing their electron-hole weights and spatial wave functions. We show that with the increase in strain magnitude, the absorption spectrum of the interlayer and intralayer excitons is red-shifted and re-ordered, and the binding energies of these layer-resolved excitons decrease monotonically and almost linearly. We derive the sensitivity of exciton binding energy to the applied strain and find that the intralayer excitons are more sensitive to strain than the interlayer excitons. For instance, a sensitivity of −7.9 meV/% is derived for the intra-MoSe2-layer excitons, which is followed by −7.4 meV/% for the intra-WSe2-layer excitons, and by −4.2 meV/% for the interlayer excitons. Our results indicate that interlayer and intralayer excitons in vertically stacked MoSe2/WSe2 heterobilayer are efficiently tunable by in-plane biaxial strain.

Authors with CRIS profile

Roland Gillen Lehrstuhl für Experimentalphysik

Involved external institutions

Nanjing University of Information Science and Technology (NUIST) / 南京信息工程大学 CN China (CN) Università degli Studi di Roma 'Tor Vergata' IT Italy (IT) University of Antwerp / Universiteit Antwerpen BE Belgium (BE)

How to cite

APA:

Li, L.L., Gillen, R., Palummo, M., Milošević, M.V., & Peeters, F.M. (2023). Strain tunable interlayer and intralayer excitons in vertically stacked MoSe2/WSe2 heterobilayers. Applied Physics Letters, 123(3). https://dx.doi.org/10.1063/5.0147761

MLA:

Li, L. L., et al. "Strain tunable interlayer and intralayer excitons in vertically stacked MoSe2/WSe2 heterobilayers." Applied Physics Letters 123.3 (2023).

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