# Seminar on Condensed Matter Theory

Group of Theoretical Physics at the Department of Condensed Matter Physics

of Charles University has a pleasure to invite you to attend the seminar

on 24th October 2024 at 13:10

at Faculty of Mathematics and Physics of Charles University, Ke Karlovu 5, 121 16 Praha 2

Seminar room **F 052**

### Artur Slobodeniuk, Ph.D.

## Effects of intra-band motion on the spectrum of excitons in 2D semiconductors

# Artur Slobodeniuk, Ph.D. » Effects of intra-band motion on the spectrum of excitons in 2D semiconductors

Location: seminar room F155KFM, Ke Karlovu 5

Transition metal dichalcogenide (TMD) monolayers remain the most interesting two-dimensional materials for optoelectronic applications due to their unique valley-dependent electronic properties. In particular, the superposition of intravalley exciton states in nonequivalent ±K points can be considered as a qubit, which can be used for various quantum technologies. The possibility of manipulation of such qubits for dark intravalley excitons with the help of intensive magnetic fields has been demonstrated in 2019 [1]. Then, a similar control for bright excitonic states by non-resonant circularly polarized light has been manifested experimentally and explained theoretically [2,3]. The theoretical analysis was based on the Semiconductor Bloch equations (SBE) where the dominant inter-band transition terms have been considered. However, this approximation is valid for small intensities of applied optical pulses only, and it should be reconsidered for the case of more intensive pulses. We analyze the solutions of the SBE where the previously neglected intra-band term, responsible for the electron dynamics within the separate bands, is taken into account. We develop the new perturbation technique and calculate the corrections to the shifts of intravalley excitons’ energies in TMD monolayers. The possibility of the experimental measurement of the obtained results is discussed.