First-principles calculations of novel sillenite compounds Bi24M2O40 (M=Se or Te)

Abstract

The electronic structures of novel sillenite compounds Bi24M2O40 (M=Se or Te) were studied by first-principles calculations. The PDOS and the band decomposed electron density contour maps projected on symmetric tetrahedral MO4 show that the novel band at the Fermi level is resulted from the antibonding interaction of cationic ns states and anionic O 2p states. Further interaction between this antibonding state and the cationic np states forms asymmetric electron densities around cation under distorted coordination. The novel band at Fermi level and the asymmetric electron densities of these two kinds of sillenite compounds may be advantageous for photocatalytic applications.