Regensburg 2019 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 17: Two-dimensional Materials I (joint session HL/CPP)

HL 17.12: Vortrag

Dienstag, 2. April 2019, 12:30–12:45, H36

Theory of Exciton-Exciton Coupling in Atomically Thin Transition Metal Dichalcogenides — •Florian Katsch, Malte Selig, and Andreas Knorr — Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, 10623 Berlin, Germany

The valley-selective circular dichroism in monolayer transition metal dichalcogenides (TMDCs) and the subsequent fast valley depolarization due to intervalley Coulomb interactions enables the study of new many-body physics in these atomically thin materials. Here, a microscopic approach is presented to describe the optical response of monolayer TMDCs dominated by strongly correlated, bound electron-hole pairs [1, 2]. The approach includes Hartree–Fock and correlation effects up to two excitonic excitations [3], as well as TMDC typical Coulomb intra- and intervalley coupling and exciton-phonon interactions [4]. The developed theory is applied to access the exciton dynamics in the coherent limit and contributes to the understanding of valley-selective pump-probe experiments [5, 6].
[1] A. L. Ivanov and H.  Haug, Phys. Rev. B 48, 1490 (1993).
[2] F. Katsch et. al., Phys. Status Solidi B, 1800185 (2018).
[3] V. M. Axt and A. Stahl, Z. Phys. B 93, 2 (1994).
[4] M. Selig et. al., 2D Mater. 5, 035017 (2018).
[5] C. Mai et. al., Nano Lett. 14, 202 (2013).
[6] R. Schmidt et. at., Nano Lett. 16, 2945 (2016).