Optical spectra of high temperature superconductors

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:538196

Ruvalds, J ^[1]

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1. Univ. of Virginia, Charlottesville, VA (United States). Physics Dept.

The concept of free electrons which yields the Drude description of the conductivity works surprisingly well in conventional metals. By contrast, the infrared reflectivity of the cuprate superconductors deviates dramatically from Drude behavior and thus challenges theory to explain the origin of the anomalous electron damping and the related mass divergence which has implications for the existence of a Fermi surface. The controversial key issue of the carrier concentration in cuprates needs to be resolved by a conserving analysis of the puzzling conductivity. Raman spectra of cuprates also exhibit unconventional electronic contributions over a wide frequency range up to 1 eV, and recent data provide evidence for the symmetry of the superconducting energy gap. A microscopic theory for both the optical conductivity and the Raman anomalies in cuprates derives a linear frequency variation of the damping from electron-electron collisions on a nested Fermi surface that refers to nearly parallel segments of an electron trajectory. Thus the nesting theory links the cuprate anomalies to phenomena in chromium and rare earth metals. Nesting also yields a novel mechanism for d-wave superconductivity that requires a Coulomb repulsion of intermediate strength and key nesting features that distinguish high {Tc} cuprates from other materials. 41 refs., 7 figs.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG05-84ER45113
• OSTI ID: 538196
• Report Number(s): CONF-960163--; ISBN 0-8194-2070-0
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
COPPER OXIDES
ENERGY GAP
FERMI LEVEL
HIGH-TC SUPERCONDUCTORS
MATHEMATICAL MODELS
OPTICAL PROPERTIES
RAMAN SPECTRA
SUPERCONDUCTIVITY