The elphbolt ab initio solver for the coupled electron-phonon Boltzmann\n transport equations

Abstract

elphbolt is a modern Fortran (2018 standard) code for efficiently solving the\ncoupled electron-phonon Boltzmann transport equations from first principles.\nUsing results from density functional and density functional perturbation\ntheory as inputs, it can calculate the effect of the non-equilibrium phonons on\nthe electronic transport (phonon drag) and non-equilibrium electrons on the\nphononic transport (electron drag) in a fully self-consistent manner and\nobeying the constraints mandated by thermodynamics. It can calculate the\nlattice, charge, and thermoelectric transport coefficients for the temperature\ngradient and electric fields, and the effect of the mutual electron-phonon drag\non these transport properties. The code fully exploits the symmetries of the\ncrystal and the transport-active window to allow the sampling of extremely fine\nelectron and phonon wave vector meshes required for accurately capturing the\ndrag phenomena. The coarray feature of modern Fortran, which offers native and\nconvenient support for parallelization, is utilized. The code is compact,\nreadable, well-documented, and extensible by design.\n