Infrared-absorption and photoinduced-absorption spectroscopy of semiconducting YBa sub 2 Cu sub 3 sup A O sub 6+ x ( A =16 and 18; 0 le x le 0. 3)

Journal Article · Wed May 01 00:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.10574· OSTI ID:5490478

Ye, H J; McCall, R P ^[1]; Farneth, W E; McCarron, III, E M ^[2]; Epstein, A J ^[3]

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1. Department of Physics, The Ohio State University, Columbus, Ohio 43210-1106 (USA)
2. E. I. du Pont de Nemours and Co., Inc., Central Research and Development Department, Experimental Station, Wilmington, Delaware 19880-0356 (USA)
3. Department of Physics and Department of Chemistry, The Ohio State University, Columbus, Ohio 43210-1106 (USA)

We report the infrared (ir) absorption and photoinduced absorption (PA) spectra of semiconducting YBa{sub 2}Cu{sub 3} {sup {ital A}}O{sub 6+{ital x}} for {ital A}=16 and 18 and for 0{le}{ital x}{le}0.3. We observe ten ir absorption modes for {ital x}=0.3 and report the first observation for all 11 allowed ir modes for {ital x}=0.0. The ir modes for {ital x}=0.0 and {ital x}=0.3 are nearly the same. Shifts of the ir modes with substitution of {sup 16}O with {sup 18}O are in accord with the expected role of oxygen in the various vibrational modes. The PA spectra of YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}} for pumping with 2.71-eV light across the band gap reveals the presence of a photoinduced electronic absorption band that varies with increasing oxygen content from a broad and nearly featureless peak at 1300 cm{sup {minus}1} for {ital x}=0.0, to photoinduced transitions at 750, 950, 1100, and 1300 cm{sup {minus}1} for {ital x}=0.13 and 0.20, and to a stronger PA peak centered at 950 cm{sup {minus}1} with a shoulder at 750 cm{sup {minus}1} for {ital x}=0.3. There are corresponding changes in the PA ir spectra with increasing {ital x}, with, in particular, bleaching of ir modes associated with the tetragonal {ital x}=0 lattice and enhancement of ir modes associated with the orthorhombic {ital x}=1.0 lattice. Based on our results and those from the following paper (Leng {ital et} {ital al}.), we propose a model for the formation of positively and negatively charged defects, {ital D}{sup +} and {ital D}{sup {minus}}. We suggest that while the {ital D}{sup +} defects reside on the CuO{sub 2} planes, the {ital D}{sup {minus}} defects consist of electrons initially in the conduction band for {ital x}=0.0. With increasing oxygen content, the electrons are trapped in CuO chains of increasing length and form localized {ital D}{sup {minus}} defects.

• OSTI ID: 5490478
• Journal Information: Physical Review, B: Condensed Matter; (USA), Vol. 43:13; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
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ABSORPTION SPECTRA
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INFRARED SPECTRA
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THIN FILMS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
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YTTRIUM COMPOUNDS
360204* - Ceramics
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