Novel pairing mechanism for superconductivity at a vanishing level of doping driven by critical ferroelectric modes

Abstract

Superconductivity (SC) occurring at low densities of mobile electrons is still a mystery since the standard theories do not apply in this regime. We address this problem by using a microscopic model for ferroelectric (FE) modes, which mediate an effective attraction between electrons. When the dispersion of modes, around zero momentum, is steep, forward scattering is the main pairing process and the self-consistent equation for the gap function can be solved analytically. The solutions exhibit unique features: Different momentum components of the gap function are decoupled, and at the critical regime of the FE modes, different frequency components are also decoupled. This leads to effects that can be observed experimentally: The gap function can be non-monotonic in temperature and the critical temperature can be independent of the chemical potential. The model is applicable to lightly doped polar semiconductors, in particular, strontium titanate.

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Cited by in corpus (20)

• Superconductivity in dilute SrTiO${}_3$: a review
• A possible mechanism for superconductivity in doped SrTiO3
• Anisotropic superconductivity mediated by ferroelectric fluctuations in cubic systems with spin-orbit coupling
• Multiorbital Ferroelectric Superconductivity in doped SrTiO3
• Superconductivity near a ferroelectric quantum critical point in ultralow-density Dirac materials
• Superconductivity induced by fluctuations of momentum-based multipoles
• Theory of superconductivity mediated by Rashba coupling in incipient ferroelectrics
• Superconductivity enhancement in polar metal regions of Sr${}_{0.95}$Ba${}_{0.05}$TiO${}_3$ and Sr${}_{0.985}$Ca${}_{0.015}$TiO${}_3$ revealed by the systematic Nb doping
• Theory of superconductivity in doped quantum paraelectrics
• Generalized Rashba Electron-Phonon Coupling and Superconductivity in Strontium Titanate
• Synergetic ferroelectricity and superconductivity in zero-density Dirac semimetals near quantum criticality
• Giant Grüneisen parameter in a strain-tuned superconducting quantum paraelectric: A consequence of the vanishing ferroelectric phonon energy
• Precision measurements of the AC field dependence of the superconducting transition in strontium titanate
• Domes of $T_c$ in single-band and multiband superconductors with finite-range attractive interactions
• Ferroelectricity-induced multiorbital odd-frequency superconductivity in SrTiO${}_3$
• A local maximum in the superconducting transition temperature of Nb-doped strontium titanate under uniaxial compressive stress
• Modeling polar order in compressively strained SrTiO${}_3$
• Strain-engineered interaction of quantum polar and superconducting phases
• A possible mechanism of the lifetime effects of electron pairs at the $SrTi{O}_3/LaTi{O}_3$ interface
• Effects of doping on polar order in SrTiO${}_3$ from first-principles modeling