Evidence of redistribution of the itinerant holes below Tc in Ba2 Sr2 CaCu2 O8 superconductors: A polarized x-ray-absorption study
Year: 1995
Type: article
Abstract: The microscopic electronic structure of high-quality superconducting ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8+\mathit{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 ${\mathit{p}}_{\mathit{z}}$ symmetry orbitals for itinerant holes. We observed a reproducible increase in the number of O 2${\mathit{p}}_{\mathit{x},}$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 2${\mathit{p}}_{\mathit{x},}$y holes was confirmed by an increase in the 3${\mathit{d}}^{9}$L/3${\mathit{d}}^{9}$ ratio estimated from Cu ${\mathit{L}}_{3}$ 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 (${\mathit{T}}_{\mathit{c}}$).
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1900576485