New insight into the electronic structure of a ${\mathrm{As}}_2$${\mathrm{Se}}_3$

Results of a realistic ab initio investigation of the geometric structure and electronic properties of the compound chalcogenide prototype ${\mathrm{As}}_2$${\mathrm{Se}}_3$ are presented. Structural parameters are accurate to within a few percent of their experimental values. The nature of bonding within and between layers is revealed and the character of states near the band edges is obtained, including predictions for the electron and hole effective masses.