<i>Ab initio</i> calculations of electron-charged defect interactions and low temperature mobility

Charged defects scatter electrons and control transport in materials at low temperature. Theoretical descriptions of this interaction have mainly relied on simplified effective mass models, which cannot capture the atomic details of the defect-induced perturbation potential or treat materials with complex band structures. We recently developed ab initio calculations of electron-defect (e-d) interactions due to neutral defects [1,2]. Here we present a method to calculate these interactions for charged defects and impurities. We employ Wannier functions to compute the relevant e-d matrix elements and develop an interpolation scheme to treat the long-range part of the electron-charged defect interaction. We demonstrate results for n- and p-doped silicon, including defect-limited relaxation times and mobilities, and explain subtle aspects of low temperature transport. Our approach can overcome limitations of effective mass models as it can be applied to materials with anisotropic, multi-valley, or linear band structures. It provides a powerful tool to study ionized impurity scattering and low temperature transport in complex materials.

[1] I-T. Lu, J. Park, J.-J. Zhou, M. Bernardi, npj Comput. Mater., 6, 1 (2020)
[2] I-T. Lu, J.-J. Zhou, M. Bernardi, Phys. Rev. Mater., 3, 033804 (2019)