Regensburg 2019 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

HL: Fachverband Halbleiterphysik

HL 23: Two-dimensional Materials II: graphene (joint session HL/CPP)

HL 23.3: Talk

Tuesday, April 2, 2019, 14:30–14:45, H36

Spatio-temporal dynamics in graphene — •Roland Jago, Samuel Brem, and Ermin Malic — Chalmers University of Technology, Gothenburg, Sweden

While the time- and energy resolved non-equilbirium dynamics in graphene is well understood [1], there is only little known about spatio-temporal electron dynamics. Optically excited carriers at the interfaces of inhomogeneities (e.g. p-n junctions, different substrate regions) create density and temperature gradients resulting in diffusion of carriers. Since many-particle interactions and diffusion depend on the conditions of the inhomogeneity, the transport of carriers is asymmetric and results in a photocurrent.

In this work, we apply the density matrix formalism solving the spatio-temporal graphene Bloch equations. We provide microscopic access to time-, momentum and spatially resolved optical excitation, Coulomb- and phonon-induced relaxation dynamics, and conversion of light into electrical current in graphene. The gained microscopic insights allow us to predict optimal conditions for photodetection in graphene.

[1] E. Malic and A. Knorr, Ultrafast optics and relaxation dynamics, VCH-Wiley, Berlin (2013)