Electronic properties of oxygen vacancies in La2CuO4-y.

Abstract

The electronic properties of oxygen vacancies in chemically pure ${\mathrm{La}}_{2}$Cu${\mathrm{O}}_{4}$ 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 ${\mathrm{La}}_{2}$Cu${\mathrm{O}}_{3.75}$. Our results suggest that vacancy-induced narrow bands near the Fermi level could lead to the antiferromagnetic state observed in some nonstoichiometric ${\mathrm{La}}_{2}$Cu${\mathrm{O}}_{4}$ samples.