Regensburg 2022 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 1: Topology: Majorana Physics
TT 1.8: Talk
Monday, September 5, 2022, 11:45–12:00, H10
Zero energy modes of artificial spin chains from ab initio calculations — •Bendegúz Nyári1, András Lászlóffy2, László Szunyogh1, and Balázs Újfalussy2 — 1Department of Theoretical Physics, Budapest University of Technology and Economics, Hungary — 2Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Hungary
The conditions under which Majorana zero modes (MZM) appear and their physical properties in realistic materials have been of high interest over the past few years triggered by their possible applications as fault tolerant quantum bits. The MZMs are topological states corresponding to triplet pairing at zero energy emerging in an inner gap inside the superconducting gap. However, experimentally it is very challenging to identify MZMs based solely on the spectral properties. Ab inito calculations are able to reproduce the measured spectral quantities and provide additional information on the nature of the in-gap states reported in corresponding experiments.
In this work we present ab initio calculations in the superconducting state of the in-gap density of states and the singlet and triplet order parameters for Fe chains on Nb(110) surface covered by one monolayer of Au. The Fe chains are also assumed to be in various artificial spin-spiral states. In a wide range of the spin-spiral wavelength we find an inner gap with states at zero-energy and large triplet pairing order parameter. A similar behavior to previous studies based on tight-binding models further supports the conjecture that there are MZMs in this system.