Breaking of symmetry of one-electron orbitals at oxygen vacancies in perovskite-type oxides

Abstract
Some general relationships have been derived in terms of the unrestricted Hartree-Fock method that define the conditions leading to the breaking of symmetry of one-electron orbitals at oxygen vacancies in oxides of the perovskite family. Numerical calculations of the critical values of relevant parameters have been carried out. Experimental data are discussed in the light of the results obtained.