Title: Mobile excitons in 2D semiconductors - Virtual mini-conference series

Speaker: Alexey Chernikov, Dresden University of Technology (TU Dresden), Germany


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. This can affect both the overall energy landscape, interactions with the Fermi sea of free charges [1], and the mobility of the excitations [2]. Here, I will present recent studies of exciton propagation in two-dimensional semiconductors monitored via time-resolved optical microscopy in systems free from the influence of disorder from local fluctuations of the dielectric environment [2]. I will discuss linear and non-linear phenomena arising from interactions as well as illustrate how strain-induced potentials can be used to guide excitons in 1D/2D heterostructures [3]. Finally, I will present temperature-dependent measurements of exciton diffusion challenging the established semi-classical description and indicating the role of quantum effects for exciton transport [4].

[1] K. Wagner et al., Phys. Rev. Lett. 125, 267401 (2020)
[2] A. Raja et al., Nature Nanotech. 14, 832 (2018)
[3] F. Dirnberger, J. D. Ziegler et al., Sci. Adv. (2021)
[4] K. Wagner et al., Phys. Rev. Lett. 127, 076801 (2021)

Date: 4th of November 2021 at 16:00 CET