The recently discovered magnetism of two-dimensional (2D) van der Waals crystals have attracted a lot of attention. Among these materials is CrI3 - a magnetic semiconductor exhibiting transitions between antiferromagnetic and ferromagnetic orderings under the influence of an applied magnetic field. Here, using first-principles methods based on density functional theory, we explore spin-dependent transport in tunnel junctions formed of fcc Cu (111) electrodes and a CrI3 tunnel barrier. We find about 100% spin polarization of the tunneling current for a ferromagnetically-ordered four-monolayer CrI3 and tunneling magnetoresistance of about 3,000% associated with a change of magnetic ordering in CrI3. This behavior is understood in terms of the spin and wave-vector dependent evanescent states in CrI3 which control the tunneling conductance. We find a sizable charge transfer from Cu to CrI3 which adds new features to the mechanism of spin-filtering in CrI3-based tunnel junctions. Our results elucidate the mechanisms of spin filtering in CrI3 tunnel junctions and provide important insights for the design of magnetoresistive devices based on 2D magnetic crystals.
@article{arxiv.1901.05993,
title = {Spin filtering in CrI$_3$ tunnel junctions},
author = {Tula R. Paudel and Evgeny Y. Tsymbal},
journal= {arXiv preprint arXiv:1901.05993},
year = {2019}
}