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TT: Fachverband Tiefe Temperaturen
TT 2: Graphene: Theory
(Joint session of DS, DY, HL, MA, O and TT organized by HL)
TT 2.4: 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.