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arXiv · 1109.2953

Competing many-body instabilities and unconventional superconductivity in graphene

Maximilian Kiesel·Christian Platt·Werner Hanke·Dmitry A. Abanin·Ronny Thomale
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Abstract

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.

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Maximilian Kiesel, Christian Platt, Werner Hanke, Dmitry A. Abanin, Ronny Thomale. 2011-09-13. Competing many-body instabilities and unconventional superconductivity in graphene. https://doi.org/10.1103/physrevb.86.020507

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