JMPJournal of Modern Physics2153-1196Scientific Research Publishing10.4236/jmp.2014.56057JMP-45400ArticlesPhysics&Mathematics Oxygen Isotope Effects on <i>T<sub>c</sub></i> Related to Polaronic Superconductivity in Underdoped Cuprates .I. Kochelaev1K.A. Müller2*A.Shengelaya3Department of Physics, Tbilisi State University, Chavchavadze, Tbilisi, GeorgiaInstitute of Physics, Kazan Federal University, Kremlevskaya 18, Kazan, RussiaPhysik-Institut der Universit?t Zürich, Winterthurerstr, Zürich, Switzerland * E-mail:irmamf@bluewin.ch(KAM);09042014050647347627 February 201424 March 2014 17 April 2014© Copyright 2014 by authors and Scientific Research Publishing Inc. 2014This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/

The planar oxygen isotope effect on Tc observed in copper oxide superconductors is remarkable in that it increases from near nil at optimal doping to a value twice that derived from BCS theory in the underdoped region. This behavior is quantitatively followed by a formula proposed by Kresin and Wolf in 1994 for polarons along the c-axis. Herein it is revisited in a more transparent way, and it is pointed out that the heterogeneity of pairing is relevant and has to be taken into account to explain the unusual planar isotope effects on Tc in underdoped cuprates.

Cuprates High-Temperature Superconductivity Polarons Isotope EffectAcknowledgements

The authors thank Vladimir Kresin for bringing an earlier incomplete version of Equations (6) and (7) to their attention.

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