Unconventional superconductivity on a topological insulator
Abstract
We study proximity-induced superconductivity on the surface of a topological insulator (TI), focusing on unconventional pairing. We find that the excitation spectrum becomes gapless for any spin-triplet pairing, such that both subgap bound states and Andreev reflection is strongly suppressed. For spin-singlet pairing, the zero-energy surface state in the -wave case becomes a Majorana fermion, in contrast to the situation realized in the topologically trivial high- cuprates. We also study the influence of a Zeeman field on the surface states. Both the magnitude and direction of this field is shown to strongly influence the transport properties, in contrast to the case without TI. We predict an experimental signature of the Majorana states via conductance spectroscopy.
Cite
@article{arxiv.0911.3918,
title = {Unconventional superconductivity on a topological insulator},
author = {Jacob Linder and Yukio Tanaka and Takehito Yokoyama and Asle Sudbø and Naoto Nagaosa},
journal= {arXiv preprint arXiv:0911.3918},
year = {2015}
}
Comments
4 pages, 3 figures. Accepted for publication in Phys. Rev. Lett