Anisotropy in the near-edge absorption fine structure of YBa2Cu

Abstract

We have observed orientational anisotropy of the near-edge absorption fine structure for the Cu 2p and O 1s excitations in single crystals of YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ using electron-energy-loss spectroscopy. The O 1s absorption results suggest that O-derived holes near the Fermi level have p/sub x//sub ,//sub y/ symmetry. The Cu 2p edge is weakly anisotropic and consistent with some holes having d/sub z//sub =/ symmetry.