Crystallographic defects and impurities govern charge transport at low temperature, where the electron-defect (e-d) interactions limit the carrier mobility and manifest themselves in a wide range of phenomena of broad relevance in condensed matter physics. Theoretical treatments of e-d interactions have so far relied on heuristic approaches and analytic models. However, the band structure, electronic wave functions, and defect perturbation potential are far more complex in real materials than in these simplified models. First-principles calculations...