Berlin 2024 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 9: 2D Materials and Heterostructures: Interlayer Excitons
HL 9.2: Vortrag
Montag, 18. März 2024, 15:15–15:30, EW 201
Signatures of efficient intervalley scattering by acoustic phonons in WSe2/MoSe2 heterostructure — •Hendrik Lambers1, Nihit Saigal1, Jonas Kiemle2, Alexander W. Holleitner2, and Ursula Wurstbauer1 — 1Institute of Physics, University Münster, Germany — 2Walter Schottky Institute and Physics Department, TU Munich, Germany
The ability to host excitonic phenomena and correlated phases gives rise to many recent studies on TMDC bilayers. In particular interlayer excitons in heterobilayers are promising candidates to form coherent many body states [1]. The role of exciton-phonon interaction for the thermalization process of these interlayer excitons and the dominant type of involved phonons are of ongoing interest [2]. We employ resonant Raman scattering at cryogenic temperatures to study the exciton phonon coupling in WSe2/MoSe2 heterostructures. The resonance profiles of degenerated WSe2 A1'/E' phonon modes are significantly affected by the assembly into heterobilayers. The profiles cannot be explained only by an incoming and an outgoing resonance of a first order Raman process. Our findings indicate a higher order Raman scattering process involving acoustic M or K point phonons of WSe2 and therefore strong interaction of acoustic phonons with electronic states, that results in efficient intervalley scattering of charge carriers. [1] M. Troue et al., Phys. Rev. Lett. 131, 036902 (2023). [2] M. Katzer et al., Phys. Rev B 108, L121102 (2023).
Keywords: TMDC heterobilayer; resonant Raman spectroscopy