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HL: Fachverband Halbleiterphysik

HL 74: Frontiers of electronic structure theory: 2D TMDC and excitonic effects

HL 74.3: Vortrag

Donnerstag, 19. März 2015, 11:15–11:30, MA 004

Ultra-fast transient absorption spectra of monolayer MoS2 by first principle — •Margherita Marsili¹, Deborah Prezzi¹, Davide Sangalli², and Andrea Marini² — ¹CNR Istituto di Nanoscienze S3, Modena, Italy — ²CNR ISM, Montelibretti, Italy

We compute ultrafast transient absorption spectra of MoS2 monolayers by employing a novel approach which combines density-functional and non-equilibrium Green's function theories. This approach allows the description of pump-probe optical experiments where the system is excited by an ultrashort laser pulse, and the variation of the optical response is probed at different time delays, thus providing a wealth of information on the fundamental physics of the relaxation processes. The case of monolayer MoS2 is extremely challenging due to the interplay of excitonic, electron-phonon and spin-orbit coupling effects. We describe the excitation of the MoS2 electronic system and follow the subsequent dynamics using a fully non-collinear spin formulation of the theory, including excitonic effects. The results are compared with experimental pump-probe data.