Transitions at T{gt}T{sub c} in underdoped crystals of YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} observed by resonant Raman scattering

Journal Article · Wed Jan 01 04:00:00 EST 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.55.93· OSTI ID:432525

Ruani, G; Ricci, P ^[1]

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1. Istituto di Spettroscopia Molecolare, Consiglio Nazionale delle Ricerche, via Gobetti 101, 40129 Bologna (Italy)

It has been shown that under a particular resonant condition it is possible to observe Raman interband electronic scattering between quasidegenerate bands associated with the apical oxygen around the S point of the Brillouin zone in YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} (1-2-3). The identification of the near-IR (1.16 eV) excited Raman-scattering structure observed between 200 and 700 cm{sup {minus}1} with the transition between these quasidegenerate bands at the Fermi level, which have neither CuO{sub 2} nor chain character, and the vicinity of the energy of this transition with the value of the superconducting gap, has caused us to investigate the temperature dependence of the Raman electronic scattering. We have analyzed two single crystals underdoped with different T{sub c}. The integrated intensity of the electronic background versus temperature shows a similar behavior for both samples. Singularities are observed not only at T{sub c} but also at two temperatures higher than T{sub c} at T{sup {asterisk}}=1.6 T{sub c} and T{sub D} that correspond to the appearance of a pseudogap for underdoped 1-2-3 with the same T{sub c}. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 432525
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 1 Vol. 55; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM COMPOUNDS
BARIUM OXIDES
COPPER COMPOUNDS
COPPER OXIDES
ELECTRONIC STRUCTURE
FERMI LEVEL
HIGH-TC SUPERCONDUCTORS
RAMAN SPECTROSCOPY
RESONANCE SCATTERING
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES