ELECTRONIC-STRUCTURE OF THE LA2CUO4 COMPOUND

The electronic structure of the La(1-x)Me(x)CuO(4) compound is studied . The band structure of the La2CuO4 crystal is calculated by the relat ivistic LMTO method. The present work is aimed to study the electron s tates of La, particularly the so-called incipient 4f-states, Much atte ntion is given to the role of the La atom in the formation of the ener gy spectrum of the crystal. We have measured the La M and N X-ray abso rption and emission spectra to determine the energy location of f-stat es with respect to the Fermi level. To explain the experimental data c orrectly the electronic structure of ground and several excited states of [La2Cu4O22] and [LaBaCu4O22] clusters has been calculated by the X (alpha)-scattering wave (SW) method. Our investigations reveal the ess ential role of La 4f-states in formation of the energy spectrum near t he Fermi level.