TY - JOUR
T1 - Raman-active phonons in Phonon assignment and charge-redistribution effects
AU - Osada, Minoru
AU - Kakihana, Masato
AU - Käll, Mikael
AU - Börjesson, Lars
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1997
Y1 - 1997
N2 - Phonon Raman spectra of (Formula presented) single crystals with (Formula presented) values close to 0, 0.4, and 0.8 have been investigated. Room-temperature measurements were performed in the five main polarization geometries, including the (Formula presented)-axis polarized configuration. We identify the (Formula presented) symmetry modes that are Raman allowed within the ideal body-centered-tetragonal unit cell, as well as several disorder activated phonon bands from the BiO and/or SrO layers. For an increasing degree of La doping, the (Formula presented) mode at (Formula presented) softens by (Formula presented) between (Formula presented) and (Formula presented) We attribute this softening to a weakening of the (Formula presented) bond due to a reduction in Cu and Bi valences when going from the overdoped (Formula presented) to the underdoped (Formula presented) regime.
AB - Phonon Raman spectra of (Formula presented) single crystals with (Formula presented) values close to 0, 0.4, and 0.8 have been investigated. Room-temperature measurements were performed in the five main polarization geometries, including the (Formula presented)-axis polarized configuration. We identify the (Formula presented) symmetry modes that are Raman allowed within the ideal body-centered-tetragonal unit cell, as well as several disorder activated phonon bands from the BiO and/or SrO layers. For an increasing degree of La doping, the (Formula presented) mode at (Formula presented) softens by (Formula presented) between (Formula presented) and (Formula presented) We attribute this softening to a weakening of the (Formula presented) bond due to a reduction in Cu and Bi valences when going from the overdoped (Formula presented) to the underdoped (Formula presented) regime.
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U2 - 10.1103/PhysRevB.56.2847
DO - 10.1103/PhysRevB.56.2847
M3 - Article
AN - SCOPUS:0008796632
VL - 56
SP - 2847
EP - 2851
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 0163-1829
IS - 5
ER -