Building a database of two-dimensional material properties using the SCAN functional

The strongly constrained and appropriately normed (SCAN) meta-GGA functional has reportedly performed exceptionally well for density functional theory (DFT) calculations involving different crystalline systems, accurately capturing lattice constants and van der Waals (vdW) interactions. The computational cost of SCAN is less than that of the hybrid functional methods as well. SCAN has been applied to several three-dimensional systems, but has not been widely used for two-dimensional (2D) materials such as transition metal (M) monochalcogenides (MX), M dichalcogenides (MX₂), and M trichalcogenides (MX₃). We provide a comprehensive set of data obtained by SCAN, hybrid functionals (HSE06), and PBE. Specifically, we compare lattice constants, bandgaps, and cohesive energies. We also study optical properties with the GW approximation and Bethe-Salpeter equation (BSE), using wavefunctions obtained from SCAN and PBE. Our goal is to benchmark these results and create a full database to determine how SCAN performs compared to other well established DFT functionals. This work is the terminal study for benchmarking different DFT functionals and will guide further theoretical studies involving 2D materials and electronic structure method development.