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Title: An unusual isotope effect in a high-transition-temperature superconductor

Abstract

In conventional superconductors, the electron pairing that allows superconductivity is caused by exchange of virtual phonons, which are quanta of lattice vibration. For high-transition-temperature (high-Tc) superconductors, it is far from clear that phonons are involved in the pairing at all. For example, the negligible change in Tc of optimally doped Bi2Sr2CaCu2O8 (Bi2212) upon oxygen isotope substitution (16O to 18O leads to Tc decreasing from 92 to 91 K) has often been taken to mean that phonons play an insignificant role in this material. Here we provide a detailed comparison of the electron dynamics of Bi2212 samples containing different oxygen isotopes, using angle-resolved photoemission spectroscopy. Our data show definite and strong isotope effects. Surprisingly, the effects mainly appear in broad high-energy humps, commonly referred to as ''incoherent peaks''. As a function of temperature and electron momentum, the magnitude of the isotope effect closely correlates with the superconducting gap--that is, the pair binding energy. We suggest that these results can be explained in a dynamic spin-Peierls picture, where the singlet pairing of electrons and the electron-lattice coupling mutually enhance each other.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Director. Office of Science. Office of Basic Energy Sciences. Materials Science and Engineering Division
OSTI Identifier:
842676
Report Number(s):
LBNL-56197
R&D Project: 507501; TRN: US0503631
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Journal Article
Resource Relation:
Other Information: Journal Publication Date: July 8, 2004
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BINDING ENERGY; ELECTRONS; ISOTOPE EFFECTS; LATTICE VIBRATIONS; OXYGEN ISOTOPES; PHONONS; PHOTOEMISSION; SPECTROSCOPY; SUPERCONDUCTIVITY; SUPERCONDUCTORS; superconductivity cuprate isotope angle-resolved photoelectron spectroscopy

Citation Formats

Gweon, G -H, Sasagawa, T, Zhou, S Y, Graf, J, Takagi, H, Lee, D -H, and Lanzara, A. An unusual isotope effect in a high-transition-temperature superconductor. United States: N. p., 2004. Web. doi:10.1038/nature02731.
Gweon, G -H, Sasagawa, T, Zhou, S Y, Graf, J, Takagi, H, Lee, D -H, & Lanzara, A. An unusual isotope effect in a high-transition-temperature superconductor. United States. doi:10.1038/nature02731.
Gweon, G -H, Sasagawa, T, Zhou, S Y, Graf, J, Takagi, H, Lee, D -H, and Lanzara, A. Thu . "An unusual isotope effect in a high-transition-temperature superconductor". United States. doi:10.1038/nature02731. https://www.osti.gov/servlets/purl/842676.
@article{osti_842676,
title = {An unusual isotope effect in a high-transition-temperature superconductor},
author = {Gweon, G -H and Sasagawa, T and Zhou, S Y and Graf, J and Takagi, H and Lee, D -H and Lanzara, A},
abstractNote = {In conventional superconductors, the electron pairing that allows superconductivity is caused by exchange of virtual phonons, which are quanta of lattice vibration. For high-transition-temperature (high-Tc) superconductors, it is far from clear that phonons are involved in the pairing at all. For example, the negligible change in Tc of optimally doped Bi2Sr2CaCu2O8 (Bi2212) upon oxygen isotope substitution (16O to 18O leads to Tc decreasing from 92 to 91 K) has often been taken to mean that phonons play an insignificant role in this material. Here we provide a detailed comparison of the electron dynamics of Bi2212 samples containing different oxygen isotopes, using angle-resolved photoemission spectroscopy. Our data show definite and strong isotope effects. Surprisingly, the effects mainly appear in broad high-energy humps, commonly referred to as ''incoherent peaks''. As a function of temperature and electron momentum, the magnitude of the isotope effect closely correlates with the superconducting gap--that is, the pair binding energy. We suggest that these results can be explained in a dynamic spin-Peierls picture, where the singlet pairing of electrons and the electron-lattice coupling mutually enhance each other.},
doi = {10.1038/nature02731},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2004},
month = {4}
}