Effects of structure and doping on the electronic properties of La2CuO4 and Nd2CuO4

Abstract

We have calculated the electronic structure of Nd 2 CuO 4 in the observed T' structure and also in hypothetical T and T ∗ structures with the linear-muffin-tin-orbital method in the atomic-sphere-approximation (LMTO-ASA). We also studied in these local density approximation (LDA) calculations the effects of Ce and Sr doping by supercell calculations. We find that the O partial density of states of the NdO 2 planes substantially shifts in energy as a function of doping and structure. By comparing our results with a similar study on La 2 CuO 4 , we note that the position of the Ln 5d states (Ln=La, Nd) through hybridization with the 2p O states in the LnO 2 planes, determines the energy shifts of these O p bands. Upon doping with Ce or Sr, the metal d-oxygen p hybridization in the Nd 1− x Ce x O 2 and Nd 1− y Sr y O 2 planes gives rise to a local energy shift of the O p bands.