Accurate electronic and optical properties of bulk antiferromagnet CrSBr via a tuned hybrid density functional with on-site corrections

Abstract: CrSBr, a layered antiferromagnet, is emerging as a versatile platform for exploring strong coupling between optical and magnetic properties in low dimensions. While experimental research on this material has progressed at a rapid pace, reliable results on the ab initio front are limited to the domain of self-consistent, many-body perturbation theory, which is both computationally expensive and technically challenging. We present an alternate, less-demanding approach -- rooted in generalized Kohn-Sham density functional theory -- that can deliver accurate electronic structure and optical absorption spectra of CrSBr, as well as quantitively accurate predictions of coupling of excitons to magnetic order in CrSBr. Using a minimal two-parameter set that can be tuned to reproduce a couple of well-known experimental and/or theoretical benchmarks, such as fundamental and optical gaps, we demonstrate excellent predictive capability for the tuned functional. The approach presented here can potentially be applied broadly to other magnetic semiconductors, complementing and simplifying current approaches to modeling these materials.