Density functional theory total energies and equilibrium volumes of LaSUB2/SUBCuOSUB4/SUBand LaSUB1.5/SUBSrSUB0.5/SUBCuOSUB4/SUB

摘要

The authors have calculated the total energy and equilibrium volumes of La2CuO4and La1.5Sr0.5CuO4using the local density approximation to density functional theory (DFT). The calculations were performed using the ASA LMTO method under the constraint of a fixed c/a ratio. The calculated equilibrium volumes are in good agreement with experiment indicating that DFT provides a useful starting point for a discussion of the energetics of this class of superconductor. In the strontium compound they find local charge redistributions that result in holes in the p band of the out-of-plane oxygen atoms. These local charge rearrangements invalidate the use of the rigid band and virtual crystal models for describing alloying.