Electronic structure of glassy chalcogenides As4Se4 and As2Se3: a joint theoretical and experimental study.

We present an interpretation of the x-ray absorption spectra of arsenic chalcogenide glasses, As4Se4 and As2Se3, from a first-principles calculation. Our calculation identifies the atomistic origins of the observed photoemission data. The importance of structural "building blocks" present in a particular glass to the electron states is emphasized. The effects of disorder on the electronic spectra are clearly demonstrated by a significant change in the electronic density of states, originating in the breakdown of long-range order coherence in the bonding states of the building blocks. We discuss the relation between observed in situ light-induced changes and the electronic structure.