Kosterlitz-Thouless transitions in Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[delta]] thin films associated with vortex-string pairing

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

DOI:https://doi.org/10.1103/PhysRevB.50.3363· OSTI ID:7171384

Ota, T; Tsukada, I; Terasaki, I; Uchinokura, K ^[1]

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1. Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113 (Japan)

Current-voltage ([ital I]-[ital V]) characteristics and the increase of the superconducting transition temperature [ital T][sub [ital c]] as a function of the number of half-unit-cell layers [ital n] are studied for Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[delta]] thin films grown by molecular beam epitaxy. These observations are interpreted in terms of Kosterlitz-Thouless (KT) transitions associated with vortex string pairs threading the film. Considering the change in the types of the lowest free-energy excitations as a function of the size of vortex pair, we have formulated KT renormalization-group (RG) equations. They are formulated with respect to independent vortex and antivortex pairs for a distance [ital r] less than the [ital n]-dependent characteristic length [ital r][sub [ital n]], and then in terms of vortex-string and antivortex-string pairs for [ital r][gt][ital r][sub [ital n]]. RG equations of these two regions are connected by the continuity of superconducting carrier density and vortex density per area. Using experimental data obtained with Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[delta]] thin films, we have solved the RG equations. It is shown that the KT transition occurs in the vortex-string region with an interstring ln[ital r] interaction only. Our calculation successfully explains KT scaling in [ital I]-[ital V] characteristics and the relation between [ital T][sub [ital c]] and [ital n]. These results indicate that the interlayer interaction plays an important role in Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub 8+[delta]] thin films.

• OSTI ID: 7171384
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 50:5; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207 -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
665411* -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CUPRATES
FILMS
HIGH-TC SUPERCONDUCTORS
KOSTERLITZ-THOULESS THEORY
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RENORMALIZATION
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTING FILMS
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VORTICES