Reentrant superconductivity at an oxide heterointerface

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Phenomena

Background:

• Magnetic fields typically suppress superconductivity through Zeeman effects or vortex formation.
• Reentrant superconductivity, where superconductivity reappears under a magnetic field, is known in 3D but underexplored in 2D systems.
• Moiré-patterned graphene is the sole known 2D system exhibiting this phenomenon.

Purpose of the Study:

• To investigate reentrant superconductivity in two-dimensional (2D) systems beyond moiré graphene.
• To explore the role of magnetic fields in stabilizing superconductivity at the LaTiO3-KTaO3 interface.
• To understand the underlying mechanisms of unconventional superconductivity in engineered 2D heterostructures.

Main Methods:

• Fabrication of epitaxial (110)-oriented LaTiO3-KTaO3 heterostructures.
• In situ tuning of charge carrier densities using electrostatic gating.
• Measurement of superconducting properties under varying magnetic fields and carrier concentrations.

Main Results:

• Observation of reentrant superconductivity at the LaTiO3-KTaO3 interface across a broad range of tunable carrier densities.
• Demonstration that electrostatic gating allows in situ control over this phenomenon, unlike in 3D materials.
• Evidence suggesting the phenomenon arises from strong spin-orbit coupling and magnetic field-induced Fermi surface modifications.

Conclusions:

• The LaTiO3-KTaO3 interface serves as a new platform for observing and studying reentrant superconductivity in 2D systems.
• The findings highlight the potential for unconventional superconductivity driven by the interplay of spin-orbit coupling and magnetic fields in 2D materials.
• This work opens avenues for exploring novel superconducting states in engineered heterostructures.