Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 99: Superconductivity: (General) Theory 2

TT 99.10: Talk

Thursday, March 19, 2015, 17:30–17:45, H 2053

Interaction effects along the edge of a topological superconductor — •Johannes S Hofmann^1,2, Andreas P Schnyder², and Fakher Assaad¹ — ¹Institut für Theoretische Physik und Astrophysik, Würzburg, Deutschland — ²Max-Planck-Institut für Festkörperforschung, Stuttgart, Deutschland

Topological nodal superconductors, such as d_xy-wave and nodal non-centrosymmetric superconductors, exhibit protected zero-energy flat-band edge states. These zero-energy edge modes are protected by time-reversal and translation symmetry and their stability is guaranteed by the conservation of a quantized topological invariant. Here, we study the fate of these flat-band edge states in the presence of interactions. We find that Hubbard interactions lead to spontaneous breaking of time-reversal or translation symmetry at the edge of the system. For the d_xy-wave superconductor in the presence of attractive Hubbard interactions we find that the flat-band states become unstable towards the formation of a charge-density wave state or a state with s-wave type pairing correlations. Repulsive Hubbard interactions, on the other hand, induce ferromagnetic order at the edge of the d_xy-wave superconductor.