Electronic properties of oxygen vacancies in La2CuO4-y

The electronic properties of oxygen vacancies in chemically pure La2CuO4 have been investigated by the ab initio pseudofunction method using a supercell geometry. Oxygen vacancies alter the electronic structure significantly, breaking up the 2-eV-wide partially filled conduction band into narrower bands, which are only about 0.1 eV wide in La2CuO3.75. Our results suggest that vacancy-induced narrow bands near the Fermi level could lead to the antiferromagnetic state observed in some nonstoichiometric La2CuO4 samples. © 1987 The American Physical Society.