Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 80: Graphene

TT 80.6: Vortrag

Donnerstag, 15. März 2018, 10:45–11:00, H 3005

Hybrid Monte Carlo simulations the electronic Lifshitz transition in monolayer graphene — •Michael Körner¹, Dominik Smith¹, Pavel Buividovich², Maksim Ulybyshev², and Lorenz von Smekal¹ — ¹Institut für theoretische Physik, Justus Liebig Universität Gießen, 35392 Gießen, Germany — ²Institut für theoretische Physik, Universität Regensburg, 93053 Regensburg, Germany

We report on Hybrid-Monte-Carlo simulations at finite spin density of the pi-band electrons in monolayer graphene with realistic interelectron interactions. Unlike simulations at finite charge-carrier density, these are not affected by a fermion-sign problem. We nevertheless observe effects that are quite similar to observations in angle resolved photoemission spectroscopy experiments on charge doped graphene, such as an interaction-induced warping of the Fermi contours or a reduction of the bandwidth. Furthermore, we find evidence that the neckdisrupting Lifshitz transition, which occurs when the Fermi level traverses the van Hove singularity (VHS), might become a true quantum phase transition due to interactions. This is in-line with an instability of the VHS towards the formation of electronic ordered phases, which has been predicted by a variety of different theoretical approaches.