Superconductivity mediated by soft ferroelectric modes

Superconductivity in doped quantum paraelectric materials develops in proximity to a ferroelectric phase. An intimate relation between the superconducting and ferroelectric phases has been experimentally established in SrTiO3, a model incipient ferroelectric. Quantum critical fluctuations of the ferroelectric order open the possibility of a novel pairing mechanism. In this talk I will present a minimal microscopic model for the linear coupling between electrons and the ferroelectric mode (a soft transverse optical phonon) in a system with spin-orbit coupling. Remarkably, the Cooper pairing interaction resulting from this Rashba-like coupling is attractive in even-parity (s-wave) as well as odd-parity (p- wave) channels. I will show how to estimate the bare Rashba coupling and BCS pairing coupling constant with the aid of first-principles computations in SrTiO3. This approach can be easily extended to other incipient ferroelectrics and interfaces.

Host: Fernando de Juan




Hybrid Seminar, Donostia International Physics Center


Maria Navarro Gastiasoro, ISC-CNR and Sapienza University of Rome, Italy

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