We have performed microwave spectroscopy of Andreev states in superconducting weak links tailored in an InAs-Al (core-full shell) epitaxially-grown nanowire. The spectra present distinctive features, with bundles of four lines crossing when the superconducting phase difference across the weak link is 0 or π. We interpret these as arising from zero-field spin-split Andreev states. A simple analytical model, which takes into account the Rashba spin-orbit interaction in a nanowire containing several transverse subbands, explains these features and their evolution with magnetic field. Our results show that the spin degree of freedom is addressable in Josephson junctions, and constitute a first step towards its manipulation.
@article{arxiv.1810.02591,
title = {Spin-orbit splitting of Andreev states revealed by microwave spectroscopy},
author = {L. Tosi and C. Metzger and M. F. Goffman and C. Urbina and H. Pothier and Sunghun Park and A. Levy Yeyati and J. Nygård and P. Krogstrup},
journal= {arXiv preprint arXiv:1810.02591},
year = {2019}
}
Comments
13 pages, 10 figures: Version accepted in Phys. Rev. X, with extended text, additional figures, appendices and references