POLARIZED CU L-III ABSORPTION STUDY OF A BI2SR2CACU2O8 SINGLE-CRYSTAL

The polarization dependence of the Cu L(III) absorption spectrum was measured on a Bi2Sr2CaCu2O8 single crystal with linearly polarized synchrotron radiation. The Cu L(III) absorption peak shows no energy difference between the z (3d3z2-r2) and the x,y (3d(x2-y2)) component, which is consistent with the electron-energy-loss study by Nucker et al., but is different from the previous x-ray-absorption studies by Bianconi et al. and Abbate et al. The relative intensity of the z component to the x,y component was estimated to be less than 5%, suggesting a very small contribution of the Cu 3d3z2-r2 orbital to the electronic structure in the vicinity of the Fermi level.