Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 46: 2D semiconductors and van der Waals heterostructures IV (joint session HL/DS/O)

O 46.6: Talk

Tuesday, March 17, 2020, 15:15–15:30, POT 81

Excitation Induced Dephasing in Monolayer Transition Metal Dichalcogenides — •Florian Katsch, Malte Selig, and Andreas Knorr — Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, 10623 Berlin, Germany

Exceptionally strong Coulomb interactions in atomically thin transition metal dichalcogenides lead to tightly bound electron-hole pairs (excitons) dominating their linear and nonlinear optical response. The latter involves bleaching [1], energy renormalizations [2], and higher-order Coulomb correlation effects like biexcitons [3] and excitation induced dephasing (EID) [4]. Whereas bleaching, energy renormalizations, and biexcitons are widely investigated, EID in exciton dominated semiconductors so far lacks microscopic calculations. Within a Heisenberg equations of motion formalism we identify the coupling between excitons and exciton-exciton scattering continua as the most prominent process causing EID and sideband formation. Evaluating the EID for single-layers of transition metal dichalcogenides, we find a good agreement with recent experiments [5,6].
[1] M. Selig et al., Physical Review Research 1, 022007 (2019).
[2] J. Shacklette and S. Cundiff, Physical Review B 66, 045309 (2002).
[3] E. Sie et al., Physical Review B 92, 125417 (2015).
[4] H. Wang et al., Physical Review Letters 71, 1261 (1993).
[5] G. Moody et al., Nature Communications 6, 8315 (2015).
[6] E. Martin et al., arXiv preprint arXiv:1810.09834 (2018).