Effective Bands and Band-like Electron Transport in Amorphous Solids

The localization of electrons caused by atomic disorder is a well-known phenomenon. However, under which circumstances electrons remain delocalized and retain band-like characteristics even when the crystal structure is completely absent, as found in certain amorphous solids, is less well understood. To probe this phenomenon, we developed a fully first-principles description of the electronic structure and charge transport in amorphous materials, which combines a representation of the amorphous state as a composite (ensemble) of local environments and the state-of-the-art many-body electronic structure methods. Using amorphous In₂O₃ as an example, we demonstrated the accuracy of our approach in reproducing the band-like nature of the conduction electrons as well as their disorder-limited mobility. In addition, our approach reveals the physical origins responsible for the electron delocalization and survival of the band dispersions despite the absence of long-range order.