Daniel Wines1,Kamal Choudhary1,Francesca Tavazza1
National Institute of Standards and Technology1
Daniel Wines1,Kamal Choudhary1,Francesca Tavazza1
National Institute of Standards and Technology1
The search for two-dimensional (2D) magnetic materials has attracted a great deal of attention because of the experimental synthesis of 2D CrI<sub>3</sub>, which has a measured Curie temperature of 45 K. Often times, these monolayers have a higher degree of electron correlation and require more sophisticated methods beyond density functional theory (DFT). Diffusion Monte Carlo (DMC) is a correlated electronic structure method that has been demonstrated successful for calculating the electronic and magnetic properties of a wide variety of 2D and bulk systems, since it has a weaker dependence on the Hubbard parameter (U) and density functional. In this study we designed a workflow that combines DFT+U and DMC in order to treat 2D correlated magnetic systems. We chose monolayer CrX<sub>3</sub> (X = I, Br, Cl, F), with a stronger focus on CrI<sub>3</sub> and CrBr<sub>3</sub>, as a case study due to the fact that they have been experimentally realized and have a finite critical temperature. With this DFT+U and DMC workflow and the analytical method of Torelli and Olsen, we estimated an upper bound of 43.56 K for the T<sub>c</sub> of CrI<sub>3</sub> and 20.78 K for the T<sub>c</sub> of CrBr<sub>3</sub>, in addition to analyzing the spin densities and magnetic properties with DMC and DFT+U. We expect that running this workflow for a well-known material class will aid in the future discovery and characterization of lesser known and more complex correlated 2D magnetic materials.