Benchmarking SCAN functional for two-dimensional crystal structures*

It has recently been reported that the strongly constrained and appropriately normed (SCAN) meta-GGA functional has performed exceptionally well for density functional theory (DFT) calculations involving molecular and crystalline systems. In addition, the computational cost of SCAN is argued to be much less than that of the highly demanding hybrid functional methods with comparable accuracy. SCAN has been applied to several three-dimensional systems, but has not been widely used for two-dimensional materials such as transition metal (M) monochalcogenides (MX), M dichalcogenides (MX₂), and M trichalcogenides (MX₃). In this study, we provide a comprehensive set of data obtained by SCAN, hybrid functionals (HSE), and PBE. Specifically, we compare lattice constants, band gaps, electronic/thermal transport and magnetic properties, and computational cost. We also study optical properties with GW approximation, using DFT orbitals obtained from SCAN and PBE. Our goal is to benchmark results from SCAN, PBE, HSE, PBE+GW, and SCAN+GW and to create a detailed picture of how SCAN performs compared to other well established DFT functionals. This work is the terminal paper for benchmarking different DFT functionals and will guide further theoretical studies involving 2D materials