Electrodynamics of ferroelectric films with negative capacitance
Résumé
We construct a theory of the electrodynamic response of ferroelectric thin films containing periodic domain textures (PDTs) with 180. polarization-oriented domains. We demonstrate that a depolarization field induced by PDTs gives rise to the negative capacitance of the ferroelectric film. We derive frequency-dependent dielectric permittivity related to the PDT dynamics across the entire frequency range. We find the resonance mode of domain oscillations in the terahertz (THz) spectral band and the singular points in the phase of the reflected THz beam that are intimately related to the negative capacitance. Our findings provide a material platform for the THz negative-capacitance-based optics of ferroelectric films and for epsilon-near-zero plasmonic THz metamaterials.