[ital a]-axis-projected electron-positron-momentum density and positron-annihilation spectra in YBa[sub 2]Cu[sub 3]O[sub 7[minus][ital x]]

Journal Article · Thu Sep 01 00:00:00 EDT 1994 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.50.6408· OSTI ID:7004975

Pankaluoto, R; Bansil, A ^[1]; Smedskjaer, L C ^[2]; Mijnarends, P E ^[3]

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1. Physics Department, Northeastern University, Boston, Massachusetts 02115 (United States)
2. Argonne National Laboratory, Argonne, Illinois 60439 (United States)
3. Interfaculty Reactor Institute, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)

We present and discuss theoretical and experimental [ital a]-axis-projected two-dimensional angular correlation of annihilation radiation (2D-ACAR) spectra from YBa[sub 2]Cu[sub 3]O[sub 7[minus][ital x]]. The experiment involved an [ital untwinned] metallic single crystal of YBa[sub 2]Cu[sub 3]O[sub 6.9] at room temperature. The calculations have been carried out within the conventional first-principles band-theory framework based on the local-density approximation; the positron state is treated in the independent-particle model. After the as-observed 2D-ACAR spectrum is corrected for an isotropic background, a good accord is found between not only the overall shape but also the fine structure in the measured and computed spectra, some discrepancies notwithstanding. Extensive analysis shows that the experimental spectrum clearly contains the signature of the electron ridge Fermi surface (FS) arising from Cu-O chains in the first Brillouin zone. Also the first and second Umklapp images of the ridge FS at higher momenta are in substantial accord with theoretical predictions. These results suggest that the electron states in Y123 are not localized, at least not strongly, along the [ital c] direction.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 7004975
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 50:9; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARIUM OXIDES
POSITRON BEAMS
COPPER OXIDES
HIGH-TC SUPERCONDUCTORS
YTTRIUM OXIDES
AMBIENT TEMPERATURE
ANGULAR CORRELATION
BAND THEORY
BRILLOUIN ZONES
FERMI LEVEL
QUATERNARY ALLOY SYSTEMS
UMKLAPP PROCESSES
ALKALINE EARTH METAL COMPOUNDS
ALLOY SYSTEMS
BARIUM COMPOUNDS
BASIC INTERACTIONS
BEAMS
CHALCOGENIDES
COPPER COMPOUNDS
CORRELATIONS
ELECTROMAGNETIC INTERACTIONS
ENERGY LEVELS
INTERACTIONS
LEPTON BEAMS
OXIDES
OXYGEN COMPOUNDS
PARTICLE BEAMS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
ZONES
665411* - Basic Superconductivity Studies- (1992-)