From deformation potential extraction to electronic transport simulations: an efficient and practical approach

In this work, we present a first-principles framework to compute the thermoelectric properties of materials based on the extraction and use of deformation potentials and then the corresponding scattering rates, which is the middle ground computationally between the constant relaxation time approximation (RTA) and first-principles relaxation time extraction. Based on density functional theory (DFT) and density functional perturbation theory (DFPT), we compute the electronic bandstructures, phonon dispersion relations, and electron-phonon matrix elements. Within the polar Wannier interpolation scheme, we consider the short-range interactions between electrons and long-wavelength phonons, and the long-range optical interactions. From the short-range electron-phonon matrix elements, we derive the acoustic deformation potential (ADP) and optical deformation potential (ODP) for long-wavelength phonons. The electronic structures and deformation potentials are taken as inputs to compute the charge transport coefficients using an advanced, home-developed numerical simulator, which allows not only for the incorporation of electron-phonon scattering, but also for other (even more) important scattering mechanisms, such as ionized impurity scattering, alloy scattering, etc.