Berlin 2018 – scientific programme

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DS: Fachverband Dünne Schichten

DS 20: 2D materials: Chalcogenides I (joint session HL/DS)

DS 20.6: Talk

Wednesday, March 14, 2018, 10:45–11:00, A 151

Theory of Exciton-Exciton Interactions in Monolayer Transition Metal Dichalcogenides — •Florian Katsch, Malte Selig, Alexander Carmele, and Andreas Knorr — Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik von Halbleitern, Technische Universität Berlin, 10623 Berlin, Germany

Due to the strong Coulomb interaction in monolayers of transition metal dichalcogenides (TMDs), the optical properties are governed by tightly bound electron-hole pairs in the vicinity of the band edge. In order to allow for efficient modeling, a theoretical description in a two particle exciton basis based on the unit-operator method [1] is introduced. The formalism incorporates TMD-typical Coulomb inter- and intravalley interactions up to three correlated excitons. The developed theory is applied to access the exciton dynamics [2,3] in the so-called coherent limit as well as exciton-phonon interactions [4]. The derived TMD Bloch equations contribute to the understanding of recent pump-probe experiments observing an immediate signal in the unpumped valley [5,6].

1ex0mm [1] A. L. Ivanov and H.  Haug, Physical Review B 48, 1490 (1993).
[2] V. M. Axt and A. Stahl, Zeitschrift für Physik B Condensed Matter [3] 93, 2 (1994).
[3] M. Lindberg et. al., Physical Review B 50, 18060 (1994).
[4] M. Selig et. al., Nature communications 7, 13279 (2016).
[5] C. Mai et. al., Nano letters 14, 202 (2013).
[6] R. Schmidt et. at., Nano letters 16, 2945 (2016).