Photoinduced self-localized structural distortions in YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/
Photoinduced absorption measurements of YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ (delta = 0.75) from 150 to 4000 cm/sup -1/ are reported. We observed photoinduced infrared-active vibrational modes, associated phonon bleachings, and an electronic transition from a self-localized gap state. The results indicate a local tetragonal to orthorhombic distortion around the charge carriers. The dynamic mass associated with the distortion is smaller in YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ than in La/sub 2/CuO/sub 4/. The photoinduced structural distortion and the associated self-localized gap state demonstrate that the photoexcitations are polarons or bipolarons. Since these photoinduced absorption features are not observed in the isostructural compound La/sub 2/NiO/sub 4/ we conclude that polaron (or bipolaron) formation may play an important role in the high-temperature superconductivity.
- Research Organization:
- Department of Physics, Institute for Polymers and Organic Solids, University of California, Santa Barbara, Santa Barbara, California 93106
- OSTI ID:
- 6781749
- Journal Information:
- Phys. Rev. B: Condens. Matter; (United States), Vol. 38:10
- Country of Publication:
- United States
- Language:
- English
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARIUM OXIDES
ELECTRONIC STRUCTURE
INFRARED SPECTRA
POLARONS
COPPER OXIDES
YTTRIUM OXIDES
CHARGE CARRIERS
ELECTRON-PHONON COUPLING
ENERGY GAP
OPTICAL PROPERTIES
PHYSICAL RADIATION EFFECTS
SUPERCONDUCTIVITY
TRANSITION TEMPERATURE
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
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ELECTRICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
QUASI PARTICLES
RADIATION EFFECTS
SPECTRA
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
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