Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 68: Transport: Majorana Fermions
TT 68.1: Vortrag
Donnerstag, 10. März 2016, 10:30–10:45, H19
Edge instabilities of topological superconductors — •Johannes S. Hofmann1,2, Fakher F. Assaad1, and Andreas P. Schnyder2 — 1Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Germany — 2Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
Nodal topological superconductors display zero-energy Majorana flat bands at generic edges. The flatness of these edge bands, which is protected by time-reversal and translation symmetry, gives rise to an extensive ground state degeneracy and a diverging density of states. Therefore, even arbitrarily weak interactions lead to an instability of the flat-band edge states towards time-reversal and translation-symmetry broken phases, which lift the ground-state degeneracy. Here, we employ Monte Carlo simulations combined with mean-field considerations to examine the instabilities of the flat-band edge states of dxy-wave superconductors. We find that attractive interactions induce a complex s-wave pairing instability together with a density wave instability. Repulsive interactions, on the other hand, lead to ferromagnetism mixed with spin-triplet pairing at the edge. We discuss the implications of our findings for experiments on cuprate high-temperature superconductors.