Size of the BCS ratio in strongly underdoped high-T{sub c} cuprates

Journal Article · Sat Mar 01 00:00:00 EST 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.55.R6149· OSTI ID:510616

Abrikosov, A A ^[1]

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1. Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

An explanation is proposed of the huge (over 20) BCS ratio 2{Delta}(0)/T{sub c} discovered recently in strongly underdoped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8{minus}{delta}}. Since no marked shrinking of the Fermi surface was found, our explanation is based on the idea of disruption of the connection between CuO{sub 2} bilayers due to reduction of localized centers providing resonant tunneling between the layers. An increase of phase fluctuations of the order parameter, mostly due to spontaneous vortex formation, leads to a possibility of a drastic reduction of T{sub c}, which practically coincides with T{sub BKT}, the temperature of the Berezinsky-Kosterlitz-Thouless transition. At the same time, the local energy gap is likely to undergo no major changes. An argument is given why at not too small concentrations of the localized centers the critical temperature can remain rather stable, despite strong variations in the normal {ital c}-axis conductivity. {copyright} {ital 1997} {ital The American Physical Society}

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 510616
• Journal Information: Physical Review, B: Condensed Matter, Vol. 55, Issue 10; Other Information: PBD: Mar 1997
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
BISMUTH OXIDES
CRITICAL TEMPERATURE
STRONTIUM OXIDES
CALCIUM OXIDES
COPPER OXIDES
HIGH-TC SUPERCONDUCTORS
ENERGY GAP
FERMI LEVEL
ORDER PARAMETERS
TUNNEL EFFECT