Electronic Structure Calculations under Periodic Boundary Conditions Based on the Gaussian and Fourier Transform (GFT) Method

We developed the Gaussian and Fourier transform method for crystalline systems. In this method, the Hartree (Coulomb) term of valence electron contribution is taken into account by solving the Poisson equation based on Fourier transform technique. We compared the band structures obtained by the Hartee-Fock (HF) approximation and the density functional theory (DFT). We used three different types of density functional approximations such as the local density approximation (LDA), generalized gradient approximation (GGA), and hybrid density functional. In this paper, we confirm that our calculation technique yields similar results to previous studies.