Time reversal dictates that nonmagnetic, centrosymmetric crystals cannot be spin-polarized as a whole. However, it has been recently shown that the electronic structure in these crystals can in fact show regions of high spin-polarization, as long as it is probed locally in real and in reciprocal space. In this article we present the first observation of this type of compensated polarization in MoS2 bulk crystals. Using spin- and angle-resolved photoemission spectroscopy (ARPES) we directly observed a spin-polarization of more than 65% for distinct valleys in the electronic band structure. By additionally evaluating the probing depth of our method we find that these valence band states at the K point in the Brillouin zone are close to fully polarized for the individual atomic trilayers of MoS2, which is confirmed by our density functional theory calculations. Furthermore, we show that this spin-layer locking leads to the observation of highly spin-polarized bands in ARPES since these states are almost completely confined within two dimensions. Our findings prove that these highly desired properties of MoS2 can be accessed without thinning it down to the monolayer limit.
@article{arxiv.1510.04101,
title = {Quasi 2D electronic states with high spin-polarization in centrosymmetric MoS$_2$ bulk crystals},
author = {Mathias Gehlmann and Gustav Bihlmayer and Irene Aguilera and Ewa Mlynczak and Markus Eschbach and Sven Döring and Pika Gospodaric and Stefan Cramm and Beata Kardynal and Lukasz Plucinski and Stefan Blügel and Claus M. Schneider},
journal= {arXiv preprint arXiv:1510.04101},
year = {2015}
}