Estimation of spin contamination errors in DFT/plane-wave calculations of solid materials using approximate spin projection scheme

Abstract Estimation and the importance of spin contamination errors (SCEs) in theoretical calculations related to open-shell molecular systems are well known. However, there is no estimation scheme available for density functional theory (DFT)/plane-wave, a standard first-principles method for solid materials. Therefore, in this study, we established the estimation scheme of SCE in DFT/plane-wave using approximate spin projection, and the new scheme was applied to typical models with stable antiferromagnetic states to illustrate the importance of SCE correction in solid systems.