Wang D, Buixaderas E, Íñiguez J, Weerasinghe J, Wang H, Bellaiche L. Fermi resonance involving nonlinear dynamical couplings in Pb(Zr,Ti)O3 solid solutions.
PHYSICAL REVIEW LETTERS 2011;
107:175502. [PMID:
22107534 DOI:
10.1103/physrevlett.107.175502]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Indexed: 05/31/2023]
Abstract
We have used first-principles-based simulations and Raman scattering techniques to reveal a novel dynamical phenomenon in Pb(Zr,Ti)O(3) solid solutions: a Fermi resonance (FR) emerging from the nonlinear coupling between ferroelectric (FE) motions and tiltings of oxygen octahedra. This FR manifests itself as the doubling of a nominally single FE mode in a purely FE phase, when the resonant frequency of the FE mode is close to the first overtone of the tiltings. We show that the FR is the result of a nonlinear coupling that is proportional to the spontaneous polarization of the material and derive an analytical model that captures the essence of the effect.
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