  Computing electron-defect (e-d) interactions from first principles has
remained impractical due to computational cost. Here we develop an
interpolation scheme based on maximally localized Wannier functions (WFs) to
efficiently compute e-d interaction matrix elements. The interpolated matrix
elements can accurately reproduce those computed directly without
interpolation, and the approach can significantly speed up calculations of e-d
relaxation times and defect-limited charge transport. We show example
calculations of vacancy defects in silicon and copper, for which we compute the
e-d relaxation times on fine uniform and random Brillouin zone grids (and for
copper, directly on the Fermi surface) as well as the defect-limited
resistivity at low temperature. Our interpolation approach opens doors for
atomistic calculations of charge carrier dynamics in the presence of defects.
