The role of strong electron correlations in determination of band structure and charge distribution of transition metal dihalide monolayers

Electronic structure and magnetic properties of the family of first-row transition metal dihalides (TMHal₂, TM = V, Cr, Mn, Fe, Co, Ni; H = Br, I) monolayers were studied by means of density functional theory. Strong electron correlations were taken into account by implementing Hubbard U correction in a simplified scheme proposed by Dudarev et al. (U_eff). U_eff correction essentially affects electronic structure of TMHal₂ widening the band gap and witnessing their highly spin-polarized nature. Two different ligand orientations namely, H and T configurations of monolayers were considered. Unlike others, FeHal₂ monolayers tend to form H structure when U_eff correction is included.