High throughput study on magnetic ground states with Hubbard U corrections in transition metal dihalide monolayers

We present a high throughput study on magnetic ground states for 90 transition metal dihalide monolayers TMX2 using density functional theory based on a collection of Hubbard U values. Stable geometrical phases between 2H and 1T are first determined. Spin-polarized calculations show that 50 out of 55 magnetic TMX2 monolayers are energetically prone to 1T phase. Further, the magnetic ground states are determined by considering four local spin models with respect to different U values. Interestingly, 23 out of 55 TMX2 monolayers exhibit robust magnetic ground orderings which will not be changed by U values. Among them, NiCl2 with magnetic moment of 2 μB is a ferromagnetic (FM) insulator. While VX2, MnX2 (X = Cl, Br and I), PtCl2 and CoI2 monolayers have noncollinear antiferromagnetic (120°-AFM) ground states with tiny in-plane magnetic anisotropic energy indicating flexible magnetic orientation rotation. The exchange parameters for both robust FM and 120°-AFM systems are analyzed with Heisenberg model in detail. Our high throughput calculations give a systematic study on electronic and magnetic properties of TMX2 monolayers and these two dimensional materials with versatile magnetic behaviors may have great potentials on spintronic applications.