Compton profile anisotropies in Bi1.6Pb0.4Sr2Ca2Cu3O10+x superconductor

We present Compton profile (CP) anisotropies measured on the high-T-c (HTc) superconductor Bi-1.6 Pb0.4Sr2Ca2Cu3O10+x. Our results, based on measureme nts of high statistical accuracy, reveal the existence of an excess charge of about 0.8 electrons in the basal planes, possessing a rather low compone nt of momentum. This can be attributed to the strong metallic behavior of t hese planes. Furthermore, symmetric features on the directional CP differen ce indicate that Bi-O bands are not crossing the Fermi level, confirming pr evious experimental evidence that Bi-O bands are not of metallic character. (C) 1999 Elsevier Science B.V. All rights reserved.