Raman study of the copper isotope effect in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.51.16460· OSTI ID:55100

Strach, T; Ruf, T; Schoenherr, E; Cardona, M ^[1]

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1. Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, 70569 Stuttgart (Germany)

Raman spectra of isotopically pure YBa{sub 2}{sup 63}Cu{sub 3}O{sub 7{minus}{delta}} and YBa{sub 2}{sup 65}Cu{sub 3}O{sub 7{minus}{delta}} were taken at room temperature and at 20 K. We find that at room temperature the phonon line at 151 cm{sup {minus}1} shows a shift in frequency of 2.0{plus_minus}0.3 cm{sup {minus}1} with Cu isotopic substitution, while the phonon at 116 cm{sup {minus}1} does not shift within the experimental accuracy (0.05{plus_minus}0.3 cm{sup {minus}1}). Similar values are also obtained at 20 K. This proves that the phonon line at 151 cm{sup {minus}1} has predominantly Cu character and that the coupling between the Ba and Cu sublattice vibrations is very weak. Fits to the experimental data with a coupled two-mode model yield a value for the Ba admixture of the 151 cm{sup {minus}1} phonon of less than 20% and only a weak renormalization of the bare Ba and Cu phonon frequencies.

• OSTI ID: 55100
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 22 Vol. 51; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
AMBIENT TEMPERATURE
BARIUM OXIDES
COPPER OXIDES
HIGH-TC SUPERCONDUCTORS
ISOTOPE EFFECTS
PHONONS
RAMAN SPECTRA
YTTRIUM OXIDES