Optimization of Cutoff Energy and K-Point Grid Parameters for DFT Study of Pristine and Mg-Doped Silicene

Abstract

Silicene, a two-dimensional material analogous to graphene, has garnered significant interest due to its promising applications in nanoelectronics, spintronics, and optoelectronics. Doping silicene with foreign atoms, such as magnesium (Mg), can modify its properties, enhancing stability and electronic versatility. This study investigates the optimization of computational parameters for pristine and Mg-doped silicene using Density Functional Theory (DFT) simulations within the Quantum ESPRESSO framework. The convergence behavior of the plane-wave cutoff energy (Ecutwfc) and k-point grids was analyzed at doping concentrations of 3.125%, 6.25%, 12.5%, and 25% Mg. Results reveal that the optimal Ecutwfc values increase with higher doping concentrations, ranging from 60 Ry for pristine silicene to 200 Ry for 3.125% Mg doping. K-point grid analysis indicates that lower doping concentrations require relatively coarse grids, while higher concentrations demand finer grids for accurate results. This study provides a reference framework for parameter selection in doped silicene systems, offering valuable insights for future theoretical research and practical applications in the field of 2D materials.