Magnetic impurities on superconductors induce discrete bound levels inside the superconducting gap, known as Yu-Shiba-Rusinov (YSR) states. YSR levels are fully spin-polarized such that the tunneling between YSR states depends on their relative spin orientation. Here, we use scanning tunneling spectroscopy to resolve the spin dynamics in the tunneling process between two YSR states by experimentally extracting the angle between the spins. To this end, we exploit the ratio of thermally activated and direct spectral features in the measurement to directly extract the relative spin orientation between the two YSR states. We find freely rotating spins down to 7mK, indicating a purely paramagnetic nature of the impurities. Such a non-collinear spin alignment is essential not only for producing Majorana bound states but also as an outlook manipulating and moving the Majorana state onto the tip.
@article{arxiv.2012.09257,
title = {Spin-dependent tunneling between individual superconducting bound states},
author = {Haonan Huang and Jacob Senkpiel and Ciprian Padurariu and Robert Drost and Alberto Villas and Raffael L. Klees and Alfredo Levy Yeyati and Juan Carlos Cuevas and Björn Kubala and Joachim Ankerhold and Klaus Kern and Christian R. Ast},
journal= {arXiv preprint arXiv:2012.09257},
year = {2024}
}
Comments
22 pages, 7 figures, including supplementary material