Quantum Paraelectric Model for Layered Superconductors
1997; American Physical Society; Volume: 79; Issue: 23 Linguagem: Inglês
10.1103/physrevlett.79.4657
ISSN1092-0145
AutoresSubodh R. Shenoy, V. Subrahmanyam, A. R. Bishop,
Tópico(s)Magnetic and transport properties of perovskites and related materials
ResumoWe consider a Hubbard-model (H) layer of charged-carrier fraction $x\ensuremath{\ll}1$, and an rms buckling angle $s\ensuremath{\ll}1$, that is elastically and electrically coupled to anharmonic (oxygen) dipoles in a ferroelectric Bilz-model (B) layer. We find that (a) the B-layer dipoles are driven to a paraelectric phase by H-layer zero-point fluctuations; (b) the $c$-axis (dipolar, optical) and H-layer (acoustic) modes are mixed by $s$ to form ${\ensuremath{\omega}}_{\ifmmode\pm\else\textpm\fi{}}(q)$ modes; and (c) the mode exchange, enhanced by a $({\ensuremath{\omega}}_{+}^{2}\ensuremath{-}{\ensuremath{\omega}}_{\ensuremath{-}}^{2}{)}^{\ensuremath{-}1}\ensuremath{\sim}{s}^{\ensuremath{-}1}$ resonant denominator, produces dynamical local carrier pairing and 2D Anderson-Morel ${d}_{{x}^{2}{\ensuremath{-}y}^{2}}$--type superconductivity, with peaks or plateaus in ${T}_{c}(x)$.
Referência(s)