An electronic structure study of La8−xSrxCu8O20−δ (8820) single crystal using polarized X-ray absorption spectroscopy

Cu L3 and O K edge polarised X-ray absorption spectroscopy has been employed to study a three-dimensional oxygen deficient perovskite single crystal of La8−xSrxCu8O20−δ (8820) (x=1.56) for E//a, E//b and E//a^45 polarizations. A careful analysis of the data shows an unmistakable presence of the itinerant eg(x2–y2) holes in it. The density of itinerant holes increases slightly as we move from E//a to the E//b orientation. This behaviour seems to be similar to the charge aggregation taking place along b-direction in an under-doped YBCO crystal in the normal state but it is rather strange as this system does not become superconducting on further cooling. This intriguing behaviour warrants further investigation.