Dirac fermions in half-metallic ferromagnetic mixed Cr${}_{1\text{-}x}$M${}_x$PSe${}_3$ monolayers

Abstract

The electronic and magnetic properties of pristine CrPSe${}_3$ and mixed Cr${}_{1\text{-}x}$M${}_x$PSe${}_3$ (M = Zn, Cd, Hg) monolayers were studied using density functional theory including an on-site Coulomb term (DFT$+U$) and tight-binding approach (TBA). While pristine CrPSe${}_3$ monolayer has an antiferromagnetic (AFM) ground state, its alloying with MPSe${}_3$ may give rise to half-metallic ferromagnet (HMF) with high Curie temperature. The resulting monolayers demonstrate single-spin Dirac cones of mainly Cr-$d$ character located in the first Brillouin zone directly at the Fermi energy. The calculated Fermi velocities of Dirac fermions indicate very high mobility in mixed Cr${}_{1\text{-}x}$M${}_x$PSe${}_3$ monolayers, that makes this material appealing for low-dimensional spintronics applications.