Surface-induced ferromagnetism and anomalous Hall transport at Zr2S(001)

TL;DR

This study predicts that the Zr2S(001) surface becomes ferromagnetic and exhibits anomalous Hall effect due to surface-induced electronic changes, revealing new phenomena in nonmagnetic topological electrides.

Contribution

It demonstrates that surface effects induce ferromagnetism and anomalous Hall transport in Zr2S electride, a nonmagnetic layered material, through first-principles calculations.

Findings

Surface induces ferromagnetism at Zr2S(001) surface.

Surface states exhibit spin polarization and helical spin textures.

Intrinsic anomalous Hall effect arises from Berry curvature.

Abstract

Two-dimensional layered electrides possessing anionic excess electrons in the interstitial spaces between cationic layers have attracted much attention due to their promising opportunities in both fundamental research and technological applications. Using first-principles calculations, we predict that the layered bulk electride Zr2S is nonmagnetic with massive Dirac nodal-line states arising from Zr-4d cationic and interlayer anionic electrons. However, the Zr2S(001) surface increases the density of states at the Fermi level caused by the surface potential, thereby inducing a ferromagnetic order at the outermost Zr layer via the Stoner instability. Consequently, the time-reversal symmetry breaking at the surface not only generates highly spin-polarized topological surface states with intricate helical spin textures, but also hosts an intrinsic anomalous Hall effect originating from the Berry curvature generated by spin-orbit coupling. Our findings offer a playground to investigate the emergence of ferromagnetism and anomalous Hall transport at the surface of nonmagnetic topological electrides.