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

We present a high throughput study of the magnetic ground states for 90 transition metal dihalide monolayers TMX(2) 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 TMX(2) monolayers are energetically prone to the 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 TMX(2) monolayers exhibit robust magnetic ground orderings which will not be changed by the U values. Among them, NiCl(2) with a magnetic moment of 2 μ(B) is a ferromagnetic (FM) insulator, while the VX(2), MnX(2) (X = Cl, Br and I), PtCl(2) and CoI(2) monolayers have noncollinear antiferromagnetic (120°-AFM) ground states with a tiny in-plane magnetic anisotropic energy, indicating flexible magnetic orientation rotation. The exchange parameters for both robust FM and 120°-AFM systems are analyzed in detail with the Heisenberg model. Our high-throughput calculations give a systematic study of the electronic and magnetic properties of TMX(2) monolayers, and these two-dimensional materials with versatile magnetic behavior may have great potential for spintronic applications.