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Raman-active phonons of a twin-free YBa sub 2 Cu sub 3 O sub 7 crystal: A complete polarization analysis

Journal Article · · Physical Review, B: Condensed Matter; (USA)
 [1]; ;  [2];  [3]
  1. Sandia National Laboratories, Livermore, California 94551 (USA)
  2. Department of Physics, University of California-Davis, Davis, California 95616 (USA)
  3. Lawrence Livermore National Laboratory, Livermore, California 94550 (USA)
A complete Raman analysis has been performed on a high-quality YBa{sub 2}Cu{sub 3}O{sub 7} crystal made free of twins by a mechanical detwinning process. Marked {ital a}-{ital b} anisotropy is observed in the intensity of the {ital A}{sub {ital g}} phonons at 116, 335, and 495 cm{sup {minus}1}. At room temperature, the {alpha}{sub {ital y}{ital y}} component of the polarizability tensor of the 116-cm{sup {minus}1} phonon is strongly coupled to an electronic continuum, the {alpha}{sub {ital x}{ital x}} component is less strongly coupled, and the coupling of the {alpha}{sub {ital z}{ital z}} component is not apparent in the Raman line shape. {ital B}{sub 2{ital g}} and {ital B}{sub 3{ital g}} phonon pairs are reproducibly found at 70 and 83 cm{sup {minus}1}, 142 and 140 cm{sup {minus}1}, 210 and 303 cm{sup {minus}1}, and 579 and 526 cm{sup {minus}1}. Comparison of the observed {ital B}{sub 2{ital g}}-{ital B}{sub 3{ital g}} pairs to literature calculations of frequencies is made.
DOE Contract Number:
AC04-76DP00789
OSTI ID:
6883926
Journal Information:
Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 41:13; ISSN PRBMD; ISSN 0163-1829
Country of Publication:
United States
Language:
English