Band structure of La2-xSrxCuO4

Using the parallelised version of the LMTO program implemented on an array of distributed processors we have calculated the band structure of La2-xSrxCuO4 using 2x2 supercell in the CuO2 plane. Our replacement of one of the two La atoms in the basis cluster of La2CuO4 by Sr corresponds to x=0.25 which is within the superconducting doping range. We compare our results with that of La2CuO4 and existing band structures for the ordered alloy corresponding to x equal to 1 and 0.5. Our calculations show that the apical oxygens make significant charge transfers upon doping, thus conforming recent experimental results. We also discuss the connection between superconductivity and the crossing of a narrow section of a band from above the below the Fermi surface. (orig.)