Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 57: Focus Session: Many-body effects in two-dimensional materials
O 57.6: Invited Talk
Wednesday, March 9, 2016, 11:45–12:15, H16
Optical Properties and Carrier Dynamics in Transition Metal Dichalcogenides — •Alexander Steinhoff-List1, Malte Rösner1, 2, Matthias Florian1, Michael Lorke1, Christopher Gies1, Ji-Hee Kim3, Deok-Soo Kim4, Chanwoo Lee4, Gang Hee Han3, Mun Seok Jeong3, 4, Tim Wehling1, 2, and Frank Jahnke1 — 1Institut für Theoretische Physik, Universität Bremen, P.O. Box 330 440, 28334 Bremen, Germany — 2Bremen Center for Computational Materials Science, Universität Bremen, 28334 Bremen, Germany — 3Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 440-746, Republic of Korea — 4Department of Energy Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea
As two-dimensional transition metal dichalcogenides are promising candidates for optoelectronic applications, there is a strong interest in understanding the influence of excited carriers in these materials on optical properties. We present studies of absorption and photoluminescence spectra of monolayer MoS2 in the presence of excited carriers as well as carrier kinetics, based on material-realistic ab-initio band structures and interaction matrix elements. It is shown that absorption spectra are strongly modified due to band-gap renormalization and screening effects, while the photoluminescence signal can be distinctly influenced by optical excitation above or below the electronic band gap. Moreover, we present results for carrier-carrier Coulomb and carrier-phonon scattering after optical excitation of the monolayer, exhibiting ultra-fast carrier relaxation on the sub-100 fs time scale.