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Author Morr, D. K. ♦ Chubukov, A. V. ♦ Kampf, A. P. ♦ Blumberg, G.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS ♦ HIGH-TC SUPERCONDUCTORS ♦ RAMAN EFFECT ♦ YTTRIUM OXIDES ♦ BARIUM OXIDES ♦ COPPER OXIDES ♦ HUBBARD MODEL ♦ COLLECTIVE EXCITATIONS ♦ EXCHANGE INTERACTIONS ♦ RESONANCE SCATTERING ♦ STRONTIUM OXIDES ♦ CHLORIDES ♦ ANTIFERROMAGNETIC MATERIALS
Abstract Two-magnon Raman scattering is a useful tool to verify recent suggestions concerning the value of the interplanar exchange constant in antiferromagnetic two-layer systems, such as YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}}. We present a theory for Raman scattering in a two-layer antiferromagnet. We study the spectra for the electronic and magnetic excitations across the charge transfer gap within the one-band Hubbard model and derive the matrix elements for the Raman scattering cross section in a diagrammatic formalism. We analyze the effect of the interlayer exchange coupling {ital J}{sub 2} for the Raman spectra in {ital A}{sub 1{ital g}} and {ital B}{sub 1{ital g}} scattering geometries both in the nonresonant regime (when the Loudon-Fleury model is valid) and at resonance. We show that within the Loudon-Fleury approximation, a nonzero {ital J}{sub 2} gives rise to a finite signal in {ital A}{sub 1{ital g}} scattering geometry. Both in this approximation and at resonance the intensity in the {ital A}{sub 1{ital g}} channel has a peak at {ital small} transferred frequency equal to twice the gap in the spin-wave spectrum. We compare our results with experiments in YBa{sub 2}Cu{sub 3}O{sub 6.1} and Sr{sub 2}CuO{sub 2}Cl{sub 2} compounds and argue that the large value of {ital J}{sub 2} suggested in a number of recent studies is incompatible with Raman experiments in {ital A}{sub 1{ital g}} geometry. {copyright} {ital 1996 The American Physical Society.}
ISSN 01631829
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-08-01
Publisher Place United States
Journal Physical Review, B: Condensed Matter
Volume Number 54
Issue Number 5


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