We introduce a theoretical framework for computing transport coefficients for complex materials with extended states, and defect or band-tail states originating from static topological disorder. As a first example, we resolve long-standing inconsistencies between experiment and theory pertaining to the conductivity and Hall mobility for amorphous silicon and show that the Hall sign anomaly is a consequence of localized states. Next, we compute the ac conductivity of amorphous polyaniline. The method may be readily integrated with current ab initio methods.

• Received 18 June 2010

DOI:https://doi.org/10.1103/PhysRevLett.105.186602