The electronic structure of the mixed valence compound Pb3O4

Ab initio self-consistent calculations of the electronic structure of Pb 3 O 4 are presented. The calculations show that Pb 3 O 4 is a semiconductor. The calculated bandgap of 1.1 eV is smaller than the observed gap of 2.1–2.2 eV. The calculations show strong hybridization between Pb(6s) and O(2p) states. For one type of lead atom, this leads to a distribution of Pb(6s) states over two occupied energy bands, similar to the situation in PbO. For the other type of lead atom in Pb 3 O 4 the Pb(6s) states are distributed over an occupied and an unoccupied band, similar to the situation in β-PbO 2 . This clearly demonstrates that Pb 3 O 4 is a mixed valence compound, i.e. Pb(II) 2 Pb(IV)O 4 . According to the calculations, the conductivity of p-type Pb 3 O 4 is due to holes in a Pb(II)(6s) valence band and the conductivity in n -type Pb 3 O 4 is due to electrons in a Pb(IV)(6s) conduction band.