Promoting $p$-based Hall effects by $p$-$d$-$f$ hybridization in Gd-based dichalcogenides

TL;DR

This study uses first-principles calculations to explore how $p$-$d$-$f$ hybridization influences Hall effects in Gd-based dichalcogenide monolayers, revealing potential for topological spintronics and orbitronics applications.

Contribution

It demonstrates the role of $p$-$d$-$f$ hybridization and strain in tuning Hall effects and electronic structures in GdX$_2$ monolayers, a novel insight for rare-earth dichalcogenides.

Findings

GdX$_2$ exhibits significant anomalous, spin, and orbital Hall conductivities.

Strain can induce quantized charge, spin, and orbital transport via orbital inversion.

Hybridization and correlation effects critically influence Hall responses.

Abstract

We conduct a first-principles study of Hall effects in rare-earth dichalcogenides, focusing on monolayers of the H-phase EuX$_2$ and GdX$_2$, where X = S, Se, and Te. Our predictions reveal that all EuX$_2$ and GdX$_2$ systems exhibit high magnetic moments and wide bandgaps. We observe that while in case of EuX$_2$ the $p$ and $f$ states hybridize directly below the Fermi energy, the absence of $f$ and $d$ states of Gd at the Fermi energy results in $p$-like spin-polarized electronic structure of GdX$_2$, which mediates $p$-based magnetotransport. Notably, these systems display significant anomalous, spin, and orbital Hall conductivities. We find that in GdX$_2$ the strength of correlations controls the relative position of $p$, $d$ and $f$-states and their hybridization which has a crucial impact on $p$-state polarization and the anomalous Hall effect, but not the spin and orbital Hall effect. Moreover, we find that the application of strain can significantly modify the electronic structure of the monolayers, resulting in quantized charge, spin and orbital transport in GdTe$_2$ via a strain-mediated orbital inversion mechanism taking place at the Fermi energy. Our findings suggest that rare-earth dichalcogenides hold promise as a platform for topological spintronics and orbitronics.