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HL: Fachverband Halbleiterphysik

HL 85: Topological insulators (TT, jointly with DS, HL, MA)

HL 85.9: Vortrag

Donnerstag, 14. März 2013, 17:30–17:45, H18

Robustness of edge states in non-centrosymmetric superconductors — •Raquel Queiroz und Andreas P. Schnyder — Max Planck Institut für Festörperforschung, 70569 Stuttgart, Germany

Nodal superconductors without inversion symmetry have non-trivial topological properties, manifested by topologically protected flat-band edge states [1-3]. Since the bulk is not fully gapped, the edge states of nodal superconductors can in principle be susceptible to impurities, which break translational symmetries. Using recursive Green’s function techniques we study the robustness of these edge states against both magnetic and non-magnetic disorder. We show that for weak and dilute non-magnetic impurities, a finite number of mid-gap edge states remains at zero-energy. We compute the zero bias conductance of a junction between a normal lead and a non-centrosymmetric superconductor as a function of disorder strength. It is found that the flat-band edge states give rise to a nearly quantized zero-bias conductance even in the presence of non-magnetic impurities.
[1] A. P. Schnyder and S. Ryu, Phys. Rev. B 84, 060504(R) (2011)
P. M. R. Brydon, A. P. Schnyder, and C. Timm, Phys. Rev. B 84, 020501(R) (2011)
A. P. Schnyder, P. M. R. Brydon, and C. Timm, Phys. Rev. B 85, 024522 (2012)