First principle studies on the electronic structures of raspite- and scheelite-structured PbWO4 and raspite with V-o(2+)

摘要

We present first-principle calculations on the electronic structures of perfect raspite- and scheelite-structured PbWO4 (PWO). The results indicate that profiles of the electronic structures for the two types of PWO are similar to each other and the bandgap of RSP is 1.1 eV smaller than that of SSP. This bandgap difference between the two types of PWO is induced by the different coordination of W. The electronic structure of raspite-structured PWO containing oxygen vacancies V-O(2+) is also calculated. An additional energy level occurs in the forbidden band, which would induce an absorption peaking at 620 nm in the yellow region. Compared to the absorption spectra of scheelite-structured PWO with V-O(2+), it is concluded that in PWO crystals the different ligand field around V-O(2+) would not greatly affect the absorption band related to V-O(2+). (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.