Berlin 2012 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 13: Transport: Poster Session

TT 13.53: Poster

Monday, March 26, 2012, 15:00–19:00, Poster B

Topological Superconductivity in the Kitaev-Heisenberg model and the effect of impurities — •Lukas Kimme, Timo Hyart, and Bernd Rosenow — Institut für Theoretische Physik, Universität Leipzig, D-04103, Leipzig, Germany

The Kitaev-Heisenberg (KH) model describes the transition between a spin liquid and an antiferromagnet, and it is expected to be realised in iridates on the honeycomb lattice [1]. Viewing the Kitaev spin model as a Mott insulator at half filling, we investigate the competing interactions away from that limit by applying a slave boson theory. Contrary to the Heisenberg interaction the Kitaev interaction prefers topologically interesting p-wave superconductivity, which in the doped regime is robust against a comparatively strong Heisenberg coupling [2]. In the context of d-wave superconductors, understanding the effect of an isolated impurituy has contributed valuable insights into the nature of the superconducting state. In addition to scattering quasi-particles, an impurity is expected to lead to a local disruption of the strongly correlated ground state, which breaks triplet correlations in the KH model. As this effect cannot be captured in a T-matrix approach for quasi-particles, we perform a fully self-consistent numerical study of the local density of states in the vicinity of an impurity, including the modification of local superconducting order by the impurity.
G. Jackeli and G. Khaliullin, Phys. Rev. Lett. 102, 017205 (2009).
T. Hyart, A.R. Wright, G. Khaliullin and B. Rosenow, preprint arXiv:1109.6681 (2011).