Self‐consistent energy band structure of tetragonal lead oxide

Abstract

Two polymorphic modifications of lead oxide (rhombic PbO, and tetragonal hot) exist under normal conditions as enanthiomorphic crystal forms. This causes a simple transformation due to the similarity of lead sublattices /1 to 3/ and the coexistence of both forms not only in films and ceramics /4/ but also in single crystals /1, 2/.However, &Or and Rot have significantly different optical, electrical, and photoelectrical prgperties. Due to the absence of definite information about the nature and structure of energy bands in these materials the mechanisms of electronic processes in lead oxides are still unclear which complicates the application of lead oxides in electronics /4/. hot (space group Dh) by means of the self-consistent quantum-chemical method basing on the Mullikan-Ruedenberg approximations. Recently this method has been used to calculate electronic bands in alkali halides /5/, corundum /6/, and rhombic lead oxide crystals /7/.In the present note we report the results of band structure calculations of 7The calculated composition of electronic bands of PbO, shows that the highest occupied bands and the lowest free bands are built predominantly of 6s and 6p lead atomic orbitals (AO' s) and do not contain any significant part of oxygen A 0 s.The similarity of lead sublattices in -Or and PbOt and the difference in their optical and electrophysical characteristics suggests different natures of electronic bands in both crystals. The coordinates of atoms in the unit cell (UC) of PbOt and basic translational vectors were taken according to /8/, the parameters of ionisation potentials of lead 6s) 6p AW s and oxygen 2s) 2p A 0 s were defined a s in /7/ according to the data from /9/. Atomic orbitals for lead and oxygen were taken from /lo, 11/.