Theoretical study of the Raman active CDW gap mode in manganites

We report here the microscopic theory of the Raman spectra of the colossal magnetoresistive (CMR) manganite systems. The system is described by a model Hamiltonian consisting of the double exchange interaction in addition to the charge ordering interaction in the e(g) band and spin-spin interaction...

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Bibliographic Details
Published in:Journal of physics. Condensed matter 2010-09, Vol.22 (37), p.376003-376003
Main Authors: Rout, G C, Panda, Saswati, Behera, S N
Format: Article
Language:English
Subjects:
Cations - chemistry
Charge
Colossal magnetoresistance
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Density
Electrons
Exact sciences and technology
Magnetic properties and materials
Magnetotransport phenomena, materials for magnetotransport
Manganese Compounds - chemistry
Manganites
Mathematical models
Models, Theoretical
Nanotechnology - instrumentation
Order disorder
Phonons
Physics
Raman spectra
Spectra
Spectrum Analysis, Raman - instrumentation
Temperature
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Summary:We report here the microscopic theory of the Raman spectra of the colossal magnetoresistive (CMR) manganite systems. The system is described by a model Hamiltonian consisting of the double exchange interaction in addition to the charge ordering interaction in the e(g) band and spin-spin interaction among the t(2g) core electrons. Further the phonon coupling to the conduction electron density is incorporated in the model for phonons in the harmonic approximation. The spectral density function for the Raman spectra is calculated from the imaginary part of the phonon Green's function. The calculated spectra display the Raman active bare phonon peak along with the charge ordering peak. The magnetic field and temperature dependence of the charge ordering peak agrees with the 480 cm(-1) JT mode observed in the experiments. The evolution of this mode is investigated in the report.
ISSN:0953-8984
1361-648X
DOI:10.1088/0953-8984/22/37/376003