Charge-fluctuation effect on the critical temperature of layered high- T sub c superconductors

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.344· OSTI ID:6000350

Ariosa, D; Beck, H ^[1]

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1. Institut de Physique, Universite de Neuchatel, rue A.-L. Breguet 1, 2000 Neuchatel, Switzerland (CH)

The value of the superconducting critical temperature ({ital T}{sub {ital c}}) of artificially layered superconductors made out of alternating Y-Ba-Cu-O and Pr-Ba-Cu-O layers is calculated as a function of both the number of layers of pure Y-Ba-Cu-O within a unit cell of the superlattice and the thickness of the insulating (Pr-Ba-Cu-O) layer. The calculation is performed within a model of electrostatically coupled two-dimensional (2D) arrays of ultrasmall Josephson junctions. The underlying mechanism is assumed to be the depression of the Beresinskii-Kosterlitz-Thouless transition temperature ({ital T}{sub BKT}) by quantum phase fluctuations due to charging effects. The {ital T}{sub {ital c}} value of the entire structure can then be tuned by varying the charging energy that depends on the average neighborhood of a typical site in Cu-O planes of Y-Ba-Cu-O layers. Recent experiments on such structures are described very accurately by the model. Furthermore, the ratio ({ital T}{sub {ital c}}{sup ({ital n})}{minus}{ital T}{sub {ital c}}{sup (1)})/({ital T}{sub {ital c}}{sup (2)}{minus}{ital T}{sub {ital c}}{sup (1)}), where {ital T}{sub {ital c}}{sup ({ital n})} is the critical temperature of a thin film made up of {ital n} Y-Ba-Cu-O unit cells, is found to be independent of the fitting parameters. This prediction is well confirmed by available experimental data. Furthermore, the model also applies for the series of Bi- and Tl-based cuprates of general formulas Bi{sub 2}Sr{sub 2}Ca{sub {ital n}{minus}1}Cu{sub {ital n}}O{sub {ital y}} and Tl{sub 2} (1)Ba{sub 2}Ca{sub {ital n}{minus}1}Cu{sub {ital n}}O{sub {ital y}} containing {ital n} Cu-O planes per unit cell, for which the observed values of the ratio {rho}=({ital T}{sub {ital c}}{sup (3)}{minus}{ital T}{sub {ital c}}{sup (1)})/({ital T}{sub {ital c}}{sup (2)}{minus}{ital T}{sub {ital c}}{sup (1)}) agree within 10% with the predicted ones.

• OSTI ID: 6000350
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:1; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
HIGH-TC SUPERCONDUCTORS
JOSEPHSON JUNCTIONS
JUNCTIONS
LAYERS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
RARE EARTH COMPOUNDS
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES