WanTiBEXOS: A Wannier based Tight Binding code for electronic band structure, excitonic and optoelectronic properties of solids

Abstract

The Bethe–Salpeter equation (BSE) approach becomes a methodology commonly used for simulating excitonic and optical properties in computer materials sciences. However, BSE approach based directly on first principles demands a high computational cost, being prohibitive for larger systems. In order to overcome this challenge, we have developed WanTiBEXOS, a parallel computational FORTRAN code, constituted of a maximally localized Wannier functions based tight-binding (MLWF-TB) model in conjunction with BSE framework. The MLWF-TB Hamiltonian used in WanTiBEXOS package can be obtained via any density functional theory package interfaced with Wannier90 code. It's expected, due MLWF-TB formalism, a computational time reduction around one or more orders of magnitude in comparison with BSE ab initio implementations. In order to demonstrate its reliability, flexibility, efficiency and versatility of WanTiBEXOS, we simulate electronic and optical property calculations for the representative materials, including conventional bulk semiconductors, perovskites, nano-monolayer materials and van der Waals heterostructures. Program summaryProgram Title: WanTiBEXOSCPC Library link to program files:https://doi.org/10.17632/4vh76mnkv5.1Developer's repository link:https://github.com/ac-dias/wantibexosLicensing provisions: GNU General Public Licence 3.0Programming language: Fortran90 (Intel compiler)External routines: OpenMP and Intel Math Kernel Library (MKL)Nature of problem: Calculate electronic, optical, and excitonic properties of solids.Solution method: Tight-binding approach under maximally localized Wannier functions (MLWF) parametrization to describe standard electronic properties and the Bethe–Salpeter formalism for excitonic properties.