Proximity-Induced Odd-Frequency Superconductivity in a Topological Insulator
Abstract
At an interface between a topological insulator (TI) and a conventional superconductor (SC), superconductivity has been predicted to change dramatically and exhibit novel correlations. In particular, the induced superconductivity by an -wave SC in a TI can develop an order parameter with a -wave component. Here we present experimental evidence for an unexpected proximity-induced novel superconducting state in a thin layer of the prototypical TI, BiSe, proximity coupled to Nb. From depth-resolved magnetic field measurements below the superconducting transition temperature of Nb, we observe a local enhancement of the magnetic field in BiSe that exceeds the externally applied field, thus supporting the existence of an intrinsic paramagnetic Meissner effect arising from an odd-frequency superconducting state. Our experimental results are complemented by theoretical calculations supporting the appearance of such a component at the interface which extends into the TI. This state is topologically distinct from the conventional Bardeen-Cooper-Schrieffer state it originates from. To the best of our knowledge, these findings present a first observation of bulk odd-frequency superconductivity in a TI. We thus reaffirm the potential of the TI-SC interface as a versatile platform to produce novel superconducting states.
Cite
@article{arxiv.2003.12104,
title = {Proximity-Induced Odd-Frequency Superconductivity in a Topological Insulator},
author = {Jonas A. Krieger and Anna Pertsova and Sean R. Giblin and Max Döbeli and Thomas Prokscha and Christof W. Schneider and Andreas Suter and Thorsten Hesjedal and Alexander V. Balatsky and Zaher Salman},
journal= {arXiv preprint arXiv:2003.12104},
year = {2020}
}
Comments
Accepted version for publication in Physical Review Letters