Polarized x-ray-absorption study of Tl[sub 2]Ba[sub 2]CaCu[sub 2]O[sub 8] and Tl[sub 2]Ba[sub 2]Ca[sub 2]Cu[sub 3]O[sub 10]

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.10520· OSTI ID:6108521

Pellegrin, E; Nuecker, N; Fink, J ^[1]; Simmons, C T; Kaindl, G ^[2]; Bernhard, J; Renk, K F ^[3]; Kumm, G; Winzer, K ^[4]

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1. Kernforschungszentrum Karlsruhe, Institut fuer Nukleare Festkoerperphysik, P.O. Box 3640, D-76021 Karlsruhe (Germany)
2. Institut fuer Experimentalphysik, Freie Universitaet Berlin, D-14195 Berlin (Germany)
3. Fakultaet fuer Physik, Universitaet Regensburg, D-93040 Regensburg (Germany)
4. I. Physikalisches Institut, Universitaet Goettingen, D-37083 Goettingen (Germany)

Polarization-dependent measurements of the O 1[ital s] absorption edges of Tl[sub 2]Ba[sub 2]CaCu[sub 2]O[sub 8] and Tl[sub 2]Ba[sub 2]Ca[sub 2]Cu[sub 3]O[sub 10] single crystals have been performed. They give evidence for an increase of the unoccupied O 2[ital p][sub [ital x],][ital y] density of states per unit cell close to the Fermi level related to the CuO[sub 2] planes by a factor of 1.5 by insertion of the third CuO[sub 2] plane. This leads to additional charge transfer to the Tl[sub 2]O[sub 2] and Ba[sub 2]O[sub 2] layers of these self-doped systems. The average number of doped holes per CuO[sub 2] plane and per formula unit for both materials is found to be close to other [ital p]-type doped cuprate superconductors with optimized superconducting transition temperature. From the Cu 2[ital p][sub 3/2] edge of Tl[sub 2]Ba[sub 2]Ca[sub 2]Cu[sub 3]O[sub 10], a small admixture of 12[plus minus]2 % of unoccupied states with 3[ital d][sub 3[ital z]][sup 2][minus][ital r][sup 2] character to the empty Cu 3[ital d] states close to the Fermi level with predominantly 3[ital d][sub [ital x]][sup 2][minus][ital y][sup 2] symmetry was found.

• OSTI ID: 6108521
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:14; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

665411* -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION SPECTROSCOPY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
CHARGE EXCHANGE
COPPER COMPOUNDS
COPPER OXIDES
ELECTRONIC STRUCTURE
ENERGY-LEVEL DENSITY
HIGH-TC SUPERCONDUCTORS
OXIDES
OXYGEN COMPOUNDS
POLARIZATION
SPECTROSCOPY
SUPERCONDUCTORS
THALLIUM COMPOUNDS
THALLIUM OXIDES
TRANSITION ELEMENT COMPOUNDS