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Title: Anomalous shifts of oxygen-mode frequencies in La sub 2 minus x Sr sub x CuO sub 4 , YBa sub 2 Cu sub 3 O sub 7 minus. delta. and Tl sub 2 Ba sub 2 Ca sub 1 minus x Gd sub x Cu sub 2 O sub 8

Journal Article · · Physical Review, B: Condensed Matter; (USA)
OSTI ID:5748501
 [1]; ;  [2]; ;  [3];  [4]
  1. Institute for Polymers and Organic Solids, University of California, Santa Barbara, Santa Barbara, California 93106 (US) J. Stefan Institute, Jamova 39, Ljubljana, (Yugoslavia)
  2. Institute for Polymers and Organic Solids, University of California, Santa Barbara, Santa Barbara, California 93106 (US)
  3. J. Stefan Institute, Jamova 39, Ljubljana, (Yugoslavia)
  4. E. I. Du Pont de Nemours, Central Research and Development, Experimental Station, P.O. Box 80328, Wilmington, Delaware 19880-0328 (US)

Comparison of photoinduced local modes (PILM's) of insulating YBa{sub 2}Cu{sub 3}O{sub 6.3} and Tl{sub 2}Ba{sub 2}Ca{sub 1{minus}{ital x}}Gd{sub {ital x}}Cu{sub 2}O{sub 8} with Raman spectra of their metallic counterparts suggests that carrier injection anomalously increases the frequencies of phonons involving {ital z}-axis apex-oxygen motion in both the dilute (insulator) and concentrated (metallic) limit. In La{sub 2}CuO{sub 4}, we observe PILM's whose frequencies suggest a correspondence with the ghost modes'' observed in neutron scattering (Rietschel {ital et} {ital al}., Physica C 162--164, 1705 (1989)). These data, together with Raman data on apex-oxygen anharmonicity, enable us to discuss the vibronic mode couplings involved in polaron formation in the three materials.

OSTI ID:
5748501
Journal Information:
Physical Review, B: Condensed Matter; (USA), Vol. 44:1; ISSN 0163-1829
Country of Publication:
United States
Language:
English