Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 25: Disordered Quantum Systems
TT 25.4: Vortrag
Dienstag, 2. April 2019, 10:15–10:30, H23
Exceptional points and nodal-lines in disordered superconductors — •Alexander Zyuzin1 and Pascal Simon2 — 1Aalto University, Espoo, Finland — 2University Paris Sud, Orsay, France
We consider the effect of disorder on the spectrum of quasiparticles in the point-node and nodal-line superconductors. We show that the interplay of disorder, band-structure anisotropy, and the supercurrent might give rise to the non-Hermitian superconducting phase, where depending on the dimensionality of the system, the nodes in the spectrum are replaced by the bulk Fermi arc or area bounded by the exceptional points or lines, respectively. We first consider a model of the proximity-induced superconductivity in the anisotropic two-dimensional Dirac semimetal. It is shown that disorder leads to a non-Hermitian self-energy contribution resulting in a bulk Fermi arc in the gap function bounded by the exceptional points. We then consider three-dimensional nodal superconductors in the presence of the supercurrent and show that disorder scattering transforms the nodes in the spectrum of quasiparticles into a Fermi area bounded by the exceptional lines.