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Superconductivity mediated by polar modes in ferroelectric metals.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Enderlein, C 
de Oliveira, J Ferreira 
Tompsett, DA 
Saitovitch, E Baggio 
Saxena, SS 

Abstract

The occurrence of superconductivity in doped SrTiO3 at low carrier densities points to the presence of an unusually strong pairing interaction that has eluded understanding for several decades. We report experimental results showing the pressure dependence of the superconducting transition temperature, Tc, near to optimal doping that sheds light on the nature of this interaction. We find that Tc increases dramatically when the energy gap of the ferroelectric critical modes is suppressed, i.e., as the ferroelectric quantum critical point is approached in a way reminiscent to behaviour observed in magnetic counterparts. However, in contrast to the latter, the coupling of the carriers to the critical modes in ferroelectrics is predicted to be small. We present a quantitative model involving the dynamical screening of the Coulomb interaction and show that an enhancement of Tc near to a ferroelectric quantum critical point can arise due to the virtual exchange of longitudinal hybrid-polar-modes, even in the absence of a strong coupling to the transverse critical modes.

Description

Keywords

5108 Quantum Physics, 51 Physical Sciences, 5104 Condensed Matter Physics

Journal Title

Nat Commun

Conference Name

Journal ISSN

2041-1723
2041-1723

Volume Title

11

Publisher

Springer Science and Business Media LLC
Sponsorship
Economic and Social Research Council (ES/P010849/1)
Engineering and Physical Sciences Research Council (EP/K012894/1)
The Royal Society