APW Band Structure of Cubic BaPb1-xBixO3

Abstract

The self-consistent APW band calculations for the materials of the ideal perovskite structure, BaPbO 3 and BaBiO 3 and the Nail type super-cell structure BaPb 0.5 Bi 0.5 O 3 have been done using the local density approximation. In both BaPbO 3 and BaBiO 3 , the bonding-antibonding splitting of the (Pb, Bi) 6s and O 2p states makes a pair of wide bands of about 15 eV width. At the center of these s-p bands, there are non-bonding O 2p bands with about 4 eV width. The character of these bands is substantially different from the previously reported results of LAPW method. In BaPb 0.5 Bi 0.5 O 3 , due to the potential difference between Pb and Bi sites, each bonding and antibonding s-p band splits into two subbands but the split antibonding bands overlap each other slightly. This result refuses the possibility of the gap formation in the Bi-rich alloys due to the charge density wave because the ordered BaPb 0.5 Bi 0.5 O 3 offers the upper limit of the charge density in the present system. Then the origin of th...