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HL: Fachverband Halbleiterphysik

HL 19: Poster Session IV

HL 19.31: Poster

Thursday, September 30, 2021, 13:30–16:30, P

Exciton-phonon coupling in transition metal dichalcogenides revealed by ultrafast electron diffraction. — •Ahmed Hassanien, Arne Ungeheuer, Mashood Tarek Mir, Lukas Nöding, Arne Senftleben, and Thomas Baumert — Institute of Physics and CINSaT, University of Kassel, Heinrich-Plett-Strasse 40, D-34132 Kassel, Germany

Exciton-phonon coupling (EXPC) is responsible in principle for the temperature-dependence of optoelectronic and transport properties of transition metal dichalcogenides (TMDCs). The signatures of EXPC are usually observed in resonance Raman scattering [1], time-resolved transmission measurements [2], in optical absorption [3] or recently in two-dimensional electronic spectroscopy (2DES) [4]. Using a highly compact femtosecond electron diffractometer developed in our group [5], we were able to probe a polarization-dependent lattice dynamics in mechanically exfoliated few-layers ReS2. These anisotropic structural dynamics followed the photoexcitation by femtosecond laser pulses spectrally in resonance with the lowest excitonic transitions in ReS2 [6].

References:

[1] Yang, Jinho, et al. FlatChem 3 (2017): 64-70. [2] Jeong, Tae Young, et al. Acs Nano 10.5 (2016): 5560-5566. [3] Christiansen, Dominik, et al. Physical review letters 119.18 (2017): 187402. [4] Li, Donghai, et al. Nature communications 12.1 (2021): 1-9. [5] Gerbig, C., et al. New J. Phys. 17.4 (2015):043050. [6] Sim, Sangwan, et al. Nature communications 7 (2016): 13569.