Berlin 2012 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 50: Superconductivity: (General) Theory

TT 50.8: Vortrag

Freitag, 30. März 2012, 11:30–11:45, H 3010

Competing many-body instabilities and unconventional superconductivity in graphene — •Christian Platt¹, Maximilian Kiesel¹, Dmitry Abanin², Werner Hanke¹, and Ronny Thomale³ — ¹Institute for Theoretical Physics, University of Wuerzburg — ²Department of Physics, Harvard University — ³Department of Physics, Stanford University

The band structure of graphene exhibits van Hove singularities (VHS) at doping x = *1/8 away from the Dirac point. Near the VHS, interactions effects, enhanced due to the large density of states, can give rise to various many-body phases at experimentally accessible temperatures. We study the competition between different many-body instabilities in graphene using functional renormalization group (FRG). We predict a rich phase diagram, which, depending on long range hopping as well as screening strength and absolute scale of the Coulomb interaction, contains a d + id-wave superconducting (SC) phase, or a spin density wave phase at the VHS. The d + id state is expected to exhibit quantized charge and spin Hall response, as well as Majorana modes bound to vortices. In the vicinity of the VHS, we find singlet d + id-wave as well as triplet f -wave SC phases. [1] arXiv:1109.2953v1