Strain control of exciton and trion spin-valley dynamics in monolayer transition metal dichalcogenides

authored by: Z. An, P. Soubelet, Y. Zhumagulov, M. Zopf, A. Delhomme, C. Qian, P. E. Faria Junior, J. Fabian, X. Cao, J. Yang, A. V. Stier, F. Ding, J. J. Finley
Abstract: The electron-hole exchange interaction is a fundamental mechanism that drives valley depolarization via intervalley exciton hopping in semiconductor multivalley systems. Here, we report polarization-resolved photoluminescence spectroscopy of neutral excitons and negatively charged trions in monolayer Formula Presented and Formula Presented under biaxial strain. We observe a marked enhancement (reduction) on the Formula Presented triplet trion valley polarization with compressive (tensile) strain while the trion in Formula Presented is unaffected. The origin of this effect is shown to be a strain-dependent tuning of the electron-hole exchange interaction. A combined analysis of the strain-dependent polarization degree using ab initio calculations and rate equations shows that strain affects intervalley scattering beyond what is expected from strain-dependent band-gap modulations. The results evidence how strain can be used to tune valley physics in energetically degenerate multivalley systems.
Organisation(s): Institute of Solid State Physics
QuantumFrontiers
External Organisation(s): Technical University of Munich (TUM)
University of Regensburg
Type: Letter
Journal: Physical Review B
Volume: 108
ISSN: 2469-9950
Publication date: 20.07.2023
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Electronic version(s): https://doi.org/10.48550/arXiv.2303.15325 (Access: Open)
https://doi.org/10.1103/PhysRevB.108.L041404 (Access: Closed)

BibTeX

@article{a791f221613a4697b084d64a82222c5c,
title = "Strain control of exciton and trion spin-valley dynamics in monolayer transition metal dichalcogenides",
abstract = "The electron-hole exchange interaction is a fundamental mechanism that drives valley depolarization via intervalley exciton hopping in semiconductor multivalley systems. Here, we report polarization-resolved photoluminescence spectroscopy of neutral excitons and negatively charged trions in monolayer Formula Presented and Formula Presented under biaxial strain. We observe a marked enhancement (reduction) on the Formula Presented triplet trion valley polarization with compressive (tensile) strain while the trion in Formula Presented is unaffected. The origin of this effect is shown to be a strain-dependent tuning of the electron-hole exchange interaction. A combined analysis of the strain-dependent polarization degree using ab initio calculations and rate equations shows that strain affects intervalley scattering beyond what is expected from strain-dependent band-gap modulations. The results evidence how strain can be used to tune valley physics in energetically degenerate multivalley systems.",
author = "Z. An and P. Soubelet and Y. Zhumagulov and M. Zopf and A. Delhomme and C. Qian and {Faria Junior}, {P. E.} and J. Fabian and X. Cao and J. Yang and Stier, {A. V.} and F. Ding and Finley, {J. J.}",
note = "Funding Information: We gratefully acknowledge the German Science Foundation (DFG) for financial support via SPP-2244 grants (DI 2013/5-1, FI 947/8-1, and FA 971/8-1). P.S., A.D., C.Q., A.V.S., and J.J.F. additionally acknowledge the clusters of excellence MCQST (EXS-2111) and e-conversion (EXS-2089). Z.A., M.Z., X.C., J.Y., and F.D. gratefully acknowledge the European Research Council (No. QD-NOMS GA715770), and the DFG Excellence Strategy-EXC-2123 Quantum Frontiers-39083 7967. Z.A. is funded by the China Scholarship Council. Y.Z., P.E.F.J., and J.F. also acknowledge the financial support of the DFG SFB 1277 (Project-ID 314695032, projects B07 and B11). ",
year = "2023",
month = jul,
day = "20",
doi = "10.48550/arXiv.2303.15325",
language = "English",
volume = "108",
journal = "Physical Review B",
issn = "2469-9950",
publisher = "American Institute of Physics",
number = "4",
}