Dresden 2017 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 41: Layer Properties: Electrical, Optical, and Mechanical Properties II
DS 41.4: Vortrag
Donnerstag, 23. März 2017, 15:45–16:00, CHE 91
Competing order in the fermionic Hubbard model on the hexagonal graphene lattice — •Dominik Smith1, Lorenz von Smekal1, Pavel Buividovich2, and Maksim Ulybyshev2 — 1Justus-Liebig-Universität, Gießen, Deutschland — 2Universität Regensburg, Regensburg, Deutschland
We study the phase diagram of the fermionic Hubbard model on the hexagonal lattice in the space of on-site and nearest neighbor couplings with Hybrid-Monte-Carlo simulations. With pure on-site repulsion this allows to determine the critical coupling strength for spin-density wave formation with the standard approach of introducing a small mass term, explicitly breaking the sublattice symmetry. The analogous mass term for charge-density wave formation above a critical nearest-neighbor repulsion, on the other hand, would introduce a fermion sign problem. The competition between the two and the phase diagram in the space of the two coouplings can however be studied in simulations without explicit sublattice symmetry breaking. Our results compare qualitatively well with the Hartree-Fock phase diagram.