The superconducting transition metal dichalcogenides 2H-NbSe2 and 2H-NbS2 are intensively studied on account of their unique electronic properties such as Ising superconductivity, found in multi- and monolayers, with upper critical fields beyond the Pauli limit. Even in bulk crystals, there are reports of multiband superconductivity and exotic states, such as the Fulde-Ferrell-Larkin-Ovchinnikov phase. In this work, we investigate the superconducting properties of 2H-NbS2 through a detailed high-field mapping of the phase diagram by means of magnetotransport and magnetostriction experiments. We compare the phase diagram between bulk crystals and a 6~nm thick flake of 2H-NbS2 and find a drastically enhanced Maki parameter in the flake, signifying a change of the relevant pair breaking mechanism from orbital to paramagnetic pair breaking, which we attribute to an effect of enhanced spin-orbit coupling.
@article{arxiv.2404.03461,
title = {From orbital to paramagnetic pair breaking in layered superconductor 2H-NbS$_2$},
author = {Davide Pizzirani and Thom Ottenbros and Maró van Rijssel and Oleksandr Zheliuk and Yulia Kreminska and Malte Rösner and Jasper Linnartz and Anne de Visser and Nigel Hussey and Jianting Ye and Steffen Wiedmann and Maarten van Delft},
journal= {arXiv preprint arXiv:2404.03461},
year = {2025}
}