Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 28: 2D materials: Chalcogenides I (joint session HL/DS)

HL 28.7: Talk

Wednesday, March 14, 2018, 11:00–11:15, A 151

Optical spectra and bound excitons in MoTe2 from monolayer to bulk by many-body perturbation theory — •Saeideh Edalati-Boostan, Caterina Cocchi, and Claudia Draxl — Physics Department and IRIS Adlershof, Humboldt-Universität zu Berlin, Germany

Among the transition-metal dichalcogenides, MoTe2 plays a relevant role as a good candidate for light-emitting devices. In the framework of GW and the Bethe-Salpeter equation as implemented in the exciting code [1], we study optical excitations in this material as a function of dimensionality, going from mono- and bilayers to the bulk. The role of spin-orbit coupling is assessed in band structures and optical spectra with respect to the number of layers. The calculated absorption spectra are characterized by a few bound excitons in the visible region with binding energies of the order of a hundred meV [2]. Bound electron-hole pairs, which are known to be both inter- and intra-layer in bulk MoTe2 [2], are analyzed in view of quantum confinement effects. This understanding is essential to eventually use this material in van der Waals heterostructures.

[1] A. Gulans, S. Kontur, C. Meisenbichler, D. Nabok, P. Pavone, S. Rigamonti, S. Sagmeister, U. Werner, and C. Draxl, JPCM 26, 36 (2014); D. Nabok, A. Gulans, and C. Draxl, PRB 94, 035118 (2016); S. Sagmeister, and C. Draxl, PCCP 11, 4451 (2009)

[2] A. Arora, M. Drüppel, R. Schmidt, T. Deilmann, R. Schneider, M. R. Molas, Ph. Marauhn, S. M. de Vasconcellos, M. Potemski, M. Rohlfing, and R. Bratschitsch, Nat Commun. 8, 639 (2017)