Abstract
The soft mode dynamics and related properties of perovskite, ABO3-type crystals have been studied using the operator form of the model Hamiltonian proposed by Pytte. The correlations have been evaluated using the double time thermal Green’s function technique and Dyson’s equation. Without any decoupling, the higher order correlations, appearing in the dynamical equation, have been evaluated using the renormalized Hamiltonian. The dielectric properties are directly related to the optical soft mode. The phonon width and shift have been calculated for different structural phases. The analysis of the temperature dependence of microwave loss tangent and dielectric constant explains the experimental results.
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Panwar, N.S., Upadhyay, T.C. & Semwal, B.S. Soft mode dynamics of perovskite type crystals. Pramana - J Phys 33, 603–614 (1989). https://doi.org/10.1007/BF02845811
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DOI: https://doi.org/10.1007/BF02845811
Keywords
- Perovskite crystals
- tangent loss
- dielectric constant
- soft mode
- Green’s function
- Dyson’s equation
- phonon width and shift