Würzburg Physics Colloquium by Prof. Alexey Chernikov (TU Dresden)

Summary

On 29 November 2021 Prof. Alexey Chernikov from the Technische Universität Dresden will give an in-person and online scientific talk about Mobile optical excitations in low-dimensional structures at the Physikalische Kolloquium of the University Würzburg. Prof. Chernikov was appointed the new W3-professor for Ultrafast Microscopy and Photonics at the Institute of Applied Physics at TU Dresden. The professorship was established by the Cluster of Excellence ct.qmat – Complexity and Topology in Quantum Matter .

Talk Abstract

Transport of optical excitations in semiconducting solids plays a central role from both fundamental and technological perspectives. In systems with strong Coulomb interaction the propagation of optically injected carriers is dominated by excitons instead of free electrons or holes. These correlations can affect both the overall energy landscape and the interactions with vibrational modes, with a strong impact on the mobility of the excitations.
In this talk I will present recent studies focused on propagation of mobile exciton quasiparticles in semiconducting van der Waals monolayers [1] and hybrid two-dimensional materials [2]. In these systems, the electron-hole correlations present a particularly interesting case combining the properties of Wannier-Mott excitations in inorganic quantum well systems with high exciton binding energies that are more characteristic for Frenkel-like states in molecular crystals. I will discuss linear and non-linear phenomena, influence of environmental disorder [3], and present strategies to externally manipulate exciton propagation [4]. Finally, I will outline the limits of semi-classical and hopping transport in
monolayer semiconductors with indications of quantum transport phenomena [5].

[1] Phys. Rev. Lett. 120, 207401 (2018)
[2] Nano Lett. 20, 6674 (2020)
[3] Nature Nanotech. 14, 832 (2019)
[4] Science Adv. 7, eabj3066 (2021)
[5] Phys. Rev. Lett. 127, 076801 (2021)

Image: © Katja Lesser