Evidence of redistribution of the itinerant holes below Tc in Ba2Sr2CaCu2O8 superconductors: A polarized x-ray-absorption study

N. L. Saini; D. S-L. Law; P. Pudney; K. B. Garg; A. A. Menovsky; J. J. M. Franse

doi:10.1103/PhysRevB.52.6219

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Evidence of redistribution of the itinerant holes below Tc in Ba2Sr2CaCu2O8 superconductors: A polarized x-ray-absorption study

N. L. Saini, D. S-L. Law, P. Pudney, K. B. Garg, A. A. Menovsky, J. J. M. Franse

DOI 10.1103/PhysRevB.52.6219 · Physical Review B

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Abstract

The microscopic electronic structure of high-quality superconducting Bi2Sr2CaCu2O8+y (Bi2212) single crystals has been investigated in the normal and superconducting states by polarized x-ray-absorption (XAS) measurements. The O K-edge XAS results led us to conclude the presence of a significant density of pz symmetry orbitals for itinerant holes. We observed a reproducible increase in the number of O 2px,y itinerant holes accompanied by a decrease of the O K XAS transition in the upper Hubbard band (covalent holes) while going from the normal to the superconducting state of the system. The increase of O 2px,y holes was confirmed by an increase in the 3d9L/3d9 ratio estimated from Cu L3 XAS measurements. This is in agreement with earlier inverse photoemission measurements and constitutes evidence for the redistribution of the itinerant holes below the transition temperature (Tc).

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Bi2Sr2CaCu2O8+y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	85	Pressure not reported	unknown