New data on the electronic structure of La 2CuO 4 compound

Abstract

The electronic structure of La 1−xMe xCuO 4 compound is studied both theoretically and experimentally. The band structure of La 2CuO 4 crystal is calculated by relativistic LMTO method. The present work is aimed to study the electron states of La, particularly the so-called incipient 4f-states. Our results differ from those obtained previously. Much attention is given to the role of La atom in the formation of the energy spectrum of the crystal. We have measured the La M and N X-ray absorption and emission spectra to determine the energy location of f-states with respect to the Fermi level. To explain the experimental data correctly electronic structure of ground and several excited states of [La 2Cu 4O 22] and [LaBaCu 4O 22] clusters has been calculated by X α-scattering wave method. Our density-of-state curves are in good agreement with the experimental spectra. Our investigations reveal the essential role of La 4f-states in formation of the energy spectrum near the Fermi level.