First-Principles Calculation of Charge Carrier Mobility using Complex Band Structure*

We compute charge carrier mobilities from the complex band structure, using the Quantum Espresso suite and a previously developed method¹. Carriers with finite lifetimes due to scattering may be represented by Bloch states with complex energies. Our method determines the constant complex potential that must be added to a perfect crystal to induce the scattering effects seen in a crystal with defects, which we deduce from a series of complex band calculations. The mean scattering lifetime is computed from the imaginary part of this complex potential, and the carrier mobility is obtained from the scattering lifetime using the Boltzmann transport theory. Mobility is calculated for graphene, hybrid organic-inorganic perovskites, and 2D FeCl2 half-metal system, as a function of temperature due to phonon scattering, impurity and absorbed molecules.
1. Wu et al, Semicond. Sci. Tech. 31, 115016 (2016).