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DY: Fachverband Dynamik und Statistische Physik
DY 53: Poster: Quantum Dynamics, Chaos and Information; Many Body Systems
DY 53.1: Poster
Donnerstag, 19. März 2020, 15:00–18:00, P1A
Thermalization properties of a system with topological flat bands and impurities — •Stefan kleine Brüning and Thomas Dahm — Universität Bielefeld
Topological insulators posses edge states, which are gapless in contrast to the bulk states. Bi2Se3 is of particular interest, because of its relatively simple Hamiltonian and, most importantly, under the influence of a Zeeman field flat bands appear in thin stripes of this material[1].
Due to the zero group velocity of electrons in flat bands there is no thermalization for a localized initial state. The question arises how this non-thermalization behaviour and the localization changes in the presence of impurities. In this work we focus on disorder, which modifies the on-site energy of the material. The influence of this disorder is investigated numerically using time evolution. The observable of interest is a quantity which is related to the localization of the wavepacket. The behaviour of this observable under change of strength and number of impurities is compared to a situation without a flat band. To investigate the question of thermalization it is probed whether the eigenstate thermalization hypothesis holds. To do this we employ a method suggested by Steinigeweg et al.[2]. This method uses random state vectors and scaling behaviour to decide this matter.
[1] Paananen, T., & Dahm, T. Physical Review B, 87, 195447(2013).
[2] Steinigeweg, R., et al. Physical Review Letters, 112, 130403
(2014).