Universally enhanced superconductivity and coexisting ferroelectricity at oxide interfaces

Abstract

The coexistence of superconductivity and ferroelectricity is rare due to their conflicting requirements: superconductivity relies on free charge carriers, whereas ferroelectricity typically occurs in insulating systems. At LaAlO3/KTaO3 interfaces, we demonstrate the coexistence of two-dimensional superconductivity and ferroelectricity, enabled by the unique properties of KTaO3 as a quantum paraelectric. Systematic gating and poling experiments reveal a universal enhancement of the superconducting transition temperature (Tc) by 0.2-0.6 K and bistable transport properties, including hysteresis, strongly suggesting the existence of switchable ferroelectric polarization in the interfacial conducting layer. Hysteresis loops indicate robust ferroelectricity below 50 K. The Tc enhancement is attributed to ferroelectric polarization-induced reduction in dielectric constant, which narrows the interfacial potential well, confining carriers closer to the interface. The bistability arises from switchable ferroelectric polarization, which modulates the potential well depending on polarization direction. These findings establish a straightforward mechanism coupling ferroelectricity and superconductivity, providing a promising platform for exploring their interplay.

References in corpus (23)

• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• A ferroelectric-like structural transition in a metal
• Discovery of two-dimensional anisotropic superconductivity at KTaO${}_3$ (111) interfaces
• Two-dimensional superconductivity at the surfaces of KTaO3 gated with ionic liquid
• A ferroelectric quantum phase transition inside the superconducting dome of Sr${}_{1-x}$Ca${}_x$TiO${}_{3-\delta }$
• Fractal superconductivity near localization threshold
• Coupled Ferroelectricity and Superconductivity in Bilayer $T_d$-MoTe${}_2$
• Locally enhanced conductivity due to the tetragonal domain structure in LaAlO${}_3$/SrTiO${}_3$ heterointerfaces
• Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO${}_3$
• Quantum critical origin of the superconducting dome in SrTiO${}_3$
• Electric field control of disorder-tunable superconductivity and the emergence of quantum metal at an oxide interface
• Towards two-dimensional metallic behavior at LaAlO3/SrTiO3 interfaces
• Observation of two-dimensional superconductivity at the LaAlO3/KTaO3(110) heterointerface
• Superfluid stiffness of a KTaO3-based two-dimensional electron gas
• Dual-Gate Modulation of Carrier Density and Disorder in an Oxide Two-Dimensional Electron System
• Ferroelectric enhancement of superconductivity in compressively strained SrTiO${}_3$ films
• One-Dimensional Nature of Pairing and Superconductivity at the LaAlO${}_3$/SrTiO${}_3$ Interface
• New insights into the electron trapping mechanism in LaAlO_3 / SrTiO3 heterostructures
• A switchable two-dimensional electron gas based on ferroelectric Ca:SrTiO${}_3$
• 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
• Nanoscale control of the metal-insulator transition at LAO/KTO (110) and LAO/KTO (111) interfaces
• Gate-tunability of the superconducting state at the $EuO/KTa{O}_3(111)$ interface
• Electron trapping and detrapping in an oxide two-dimensional electron gas: The role of ferroelastic twin walls

Cited by in corpus (2)

• Geometric Control of Pairing: Universal Scaling of Superconductivity at KTaO3 Interfaces
• Percolative Pathway to Stripe Order in KTaO3-Based Superconductivity