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ISRN Condensed Matter Physics
Volume 2011 (2011), Article ID 961832, 5 pages
http://dx.doi.org/10.5402/2011/961832
Research Article

Theory of Isotope Effect in YBa 2 Cu 3 O 7 βˆ’ 𝜹

Department of Physics, Beijing University, Beijing 100871, China

Received 31 July 2011; Accepted 24 August 2011

Academic Editor: H. Eisaki

Copyright © 2011 Fu-sui Liu. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper is the first to demonstrate that a pure nonphonon mechanism can quantitatively explain all isotope effect experiments in YBa 2 Cu 3 O 7 βˆ’ 𝛿 (YBCO) and to conclude that the influence of zero-point oscillation on the two local spin-mediated interaction (TLSMI) causes the isotope effects in YBCO. This paper is the first to calculate the doping dependence of exponents of oxygen isotope effect for all quantities of YBCO, such as 𝑇 𝑐 , T βˆ— , pseudogap at 𝑇 𝑐 , gap at 0 K, and number density of supercurrent carriers at 0 K. This paper points out that the observed inverse isotope effect of 𝑇 𝑐 comes also from zero-point oscillation.