Regensburg 2016 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 6: Graphene: Theory
(Joint session of DS, DY, HL, MA, O and TT organized by HL)

DS 6.4: Vortrag

Montag, 7. März 2016, 10:15–10:30, H17

The Electronic Structure of Graphene from Dyson-Schwinger Equations with Partially Screened Coulomb Interactions — •Manon Bischoff¹, Katja Kleeberg², Dominik Smith², Lorenz von Smekal², and Björn Wellegehausen² — ¹Johannes Gutenberg Universität, Mainz, Deutschland — ²Justus Liebig Universität, Gießen, Deutschland

We have studied the possibility of a semimetal-insulator transition via spin-density or charge-density wave formation with partially screened Coulomb interactions in graphene from the coupled Dyson-Schwinger equations (DSEs) for the electronic excitations and their Lindhard screening on the honeycomb lattice. In the limit of purely static Lindhard screening these DSEs close on themselves and no further truncation is necessary. With appropriate boundary conditions they can then be solved numerically by fixed-point iteration. This is particularly efficient on graphical processing units (GPUs). After validating the static approximation from Monte-Carlo simulations on smaller lattices with appropriate boundary conditions, it allows to study much larger sheets than in the ab-initio simulations, e.g., to search for Miransky scaling, and to include cases where the latter break down because of a fermion-sign problem as for charge-density wave formation, for example.