Absence of a Kosterlitz-Thouless transition in ultrathin YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.54.R9674· OSTI ID:390389

Repaci, J M; Kwon, C; Li, Q; Jiang, X; Venkatessan, T; Glover, III, R E; Lobb, C J ^[1]; Newrock, R S ^[2]

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1. Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)
2. Department of Physics, University of Cincinnati, Cincinnati, Ohio 4521-0011 (United States)

We have performed nanovolt-level dc measurements on single-unit-cell films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. When only the low-sensitivity data are analyzed, they are roughly consistent with the occurrence of a Kosterlitz-Thouless transition. At the lowest currents and voltages, however, the samples are ohmic at temperatures quite far below the nominal Kosterlitz-Thouless transition temperature, contrary to the theory. The ohmic response at low currents implies that there are unbound vortices present well below the nominal Kosterlitz-Thouless transition temperature. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 390389
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 14 Vol. 54; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
COPPER OXIDES
ELECTRIC CONDUCTIVITY
HIGH-TC SUPERCONDUCTORS
KOSTERLITZ-THOULESS THEORY
MAGNETIC FLUX
MIXED STATE
PHASE TRANSFORMATIONS
SUPERCONDUCTING FILMS
YTTERBIUM OXIDES