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HL: Fachverband Halbleiterphysik

HL 35: Focus Session: Transient multi-wave mixing on excitonic resonances

HL 35.1: Hauptvortrag

Donnerstag, 30. März 2023, 09:30–10:00, POT 251

Quantum Dynamics of Polarons in Doped Semiconductor Monolayers — •Xiaoqin Elaine Li¹ and Di Huang² — ¹Physics Department, University of Texas at Austin, Austin, TX, U.S.A. — ²Physic Department, TongJi University, Shanghai, China

When mobile impurities are introduced and coupled to a Fermi sea, new quasiparticles known as Fermi polarons are formed. We study Fermi polarons in two dimensional systems, where many questions and debates regarding their nature persist. The model systems we investigate are doped MoSe2 and WSe2 monolayers. In MoSe2, we find the observed attractive and repulsive polaron energy splitting and the quantum dynamics of attractive polarons agree with the predictions of a simple theory. As the doping density increases, the quantum dephasing of the attractive polarons remains constant, indicative of stable quasiparticles, while the repulsive polaron dephasing rate increases nearly quadratically. In WSe2, two distinct species of attractive polarons exist, singlet and triplet polarons. The singlet (triplet) dynamics are mediated by the Fermi seas in the same (opposite) valley. A long-lived valley polarization component is found and likely related to a reservoir of dark states.