SKM 2021 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 25: Poster Session: Topology
TT 25.18: Poster
Donnerstag, 30. September 2021, 13:30–16:00, P
Carrier transitions in gapped Dirac systems induced by strong light pulses — •Mario Ebner1, Vanessa Junk1, Cosimo Gorini1,2, and Klaus Richter1 — 1Institut für Theoretische Physik, Universität Regensburg, Germany — 2Université Paris-Saclay, CEA, CNRS, SPEC, 91191, Gif-sur-Yvette, France
In order to understand the interesting consequences of matter interacting with strong light pulses, such as higher harmonics generation, it is necessary to investigate how the light field influences the occupation of the energy bands in the system.
We theoretically study this redistribution of carriers in a Dirac system, such as graphene, in the presence of a mass gap. This is done in two ways: Firstly, we model the behaviour of electrons in the system by a wave packet propagating under the influence of the electric field pulse. Secondly, we want to emphasize another approach similar to [1], which essentially breaks down to solving the time-dependent Schrödinger equation for a single k-mode. This gives a complementary view of the physical processes involved. In particular, we discuss the interplay between the motion in reciprocal space due to the electric field and the dipole matrix element between valence and conduction band which determines the observed populations.
As an outlook, we sketch how to deduce the resulting current which can be split in intra- and interband contributions and which can be used for computing higher harmonics spectra.
[1] S. A. O. Motlagh et al, J. Phys.: Condens. Matter 32, 065305 (2020)