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Interplay of electrong-lattice interactions and superconductivity in Bi2Sr2CaCu2O8+δ

Cornell Affiliated Author(s)

Author

J. Lee
K. Fujita
K. McElroy
J.A. Slezak
M. Wang
Y. Aiura
H. Bando
M. Ishikado
T. Masui
J.-X. Zhu
A.V. Balatsky
H. Eisaki
S. Uchida
J.C. Davis

Abstract

Formation of electron pairs is essential to superconductivity. For conventional superconductors, tunnelling spectroscopy has established that pairing is mediated by bosonic modes (phonons); a peak in the second derivative of tunnel current d2I/dV2 corresponds to each phonon mode. For high-transition-temperature (high-Tc) superconductivity, however, no boson mediating electron pairing has been identified. One explanation could be that electron pair formation and related electron-boson interactions are heterogeneous at the atomic scale and therefore challenging to characterize. However, with the latest advances in d2I/dV2 spectroscopy using scanning tunnelling microscopy, it has become possible to study bosonic modes directly at the atomic scale. Here we report d 2I/dV2 imaging studies of the high-Tc superconductor Bi2Sr2CaCu2O 8+δ. We find intense disorder of electron-boson interaction energies at the nanometre scale, along with the expected modulations in d 2I/dV2 (refs 9, 10). Changing the density of holes has minimal effects on both the average mode energies and the modulations, indicating that the bosonic modes are unrelated to electronic or magnetic structure. Instead, the modes appear to be local lattice vibrations, as substitution of 18O for 16O throughout the material reduces the average mode energy by approximately 6 per cent-the expected effect of this isotope substitution on lattice vibration frequencies. Significantly, the mode energies are always spatially anticorrelated with the superconducting pairing-gap energies, suggesting an interplay between these lattice vibration modes and the superconductivity. © 2006 Nature Publishing Group.

Date Published

Journal

Nature

Volume

442

Issue

7102

Number of Pages

546-550,

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-33746671943&doi=10.1038%2fnature04973&partnerID=40&md5=3d2bf2cae8703573c91b533ad8dfc4df

DOI

10.1038/nature04973

Group (Lab)

J.C. Seamus Davis Group

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