Electron-phonon physics from first principles using the EPW code

EPW is an open-source software for ab initio calculations of electron-phonon interactions and related materials properties. The code combines density functional perturbation theory and maximally localized Wannier functions to efficiently compute electron-phonon coupling matrix elements, and to perform predictive calculations of temperature-dependent properties and phonon-assisted quantum processes in bulk solids and low-dimensional materials. Here, we report on significant developments in the code since 2016, namely: a transport module for the calculation of charge carrier mobility under electric and magnetic fields using the Boltzmann transport equation; a superconductivity module for calculations of phonon-mediated superconductors using the anisotropic multi-band Eliashberg theory; an optics module for calculations of phonon-assisted indirect transitions; a module for the calculation of small and large polarons without supercells; and a module for calculating band structure renormalization and temperature-dependent optical spectra using the special displacement method. For each capability, we outline the methodology and implementation and provide example calculations.

Automated summary

EPW is an open-source software used for ab initio calculations of electron-phonon interactions and related materials properties. It efficiently computes electron-phonon coupling matrix elements and performs predictive calculations of temperature-dependent properties and phonon-assisted quantum processes. Recent developments include the addition of modules for calculating charge carrier mobility, phonon-mediated superconductivity, phonon-assisted indirect transitions, small and large polarons, and band structure renormalization. Examples and methodologies for each capability are provided.