Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 20: 2D Materials 4 (joint session HL/CPP/DS)
HL 20.7: Talk
Wednesday, September 7, 2022, 11:15–11:30, H36
strain tuning of exciton and trion dynamics in monolayer WSe2 at cryogenic temperatures — •zhao an1, pedro soubelet2, andreas v. stier2, michael zopf1, yaroslav zhumagullov3, jaroslav fabian3, paulo e. faria jonior3, jonathan j. finley2, and fei ding1,4 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany — 2Walter Schottky Institut and Physik Department, Technische Universität München, 85748 Garching, Germany — 3Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany — 4Laboratorium fur Nano- und Quantenengineering, Leibniz Universität Hannover, Schneiderberg 39, 30167 Hannover, Germany
Transition metal dichalcogenides (TMD) receive increasing attention these years. In TMD monolayers, the light-matter interaction is driven by strong excitonic effects. Additional to neutral excitons, singlet/ triplet trions are observed, in which the additional charge is either in the same or opposite valley with respect to excitons. We apply dynamic strain at cryogenic temperatures to investigate the exciton dynamics of monolayer WSe2. Biaxial strain is electrically controlled via a piezoelectric actuator and transferred to the hBN/WSe2/hBN. We find that next to changes in the emission energy and intensity, the singlet-triplet trion fine structure is affected. Polarization-resolved PL spectroscopy reveals that biaxial strain alters the polarizations of trions, which is attributed to changes in the pumping of resident electrons and the intervalley scattering of excitons and electrons.