Two-Dimensional Superconductivity at the LaAlO_{3}/KTaO_{3}(110) Heterointerface

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• Oxide interfaces are a frontier for discovering novel electronic phenomena.
• Two-dimensional (2D) superconductivity is of fundamental interest and potential technological importance.
• LaAlO3/KTaO3 heterostructures are emerging systems for exploring emergent electronic properties.

Purpose of the Study:

• To investigate the possibility of superconductivity at the interface between LaAlO3 and KTaO3.
• To characterize the nature and properties of the observed superconductivity.
• To establish a new material system for studying 2D superconductivity.

Main Methods:

• Fabrication of a LaAlO3 film on a KTaO3(110) single crystal substrate.
• Measurement of superconducting properties, including critical temperature (Tc) and upper critical field.
• Analysis of the superconducting transition using Berezinskii-Kosterlitz-Thouless theory.
• Carrier density measurements at low temperatures.

Main Results:

• Observation of superconductivity with a critical temperature (Tc) of approximately 0.9 K.
• Significant anisotropy in the upper critical field, indicating 2D character.
• Superconducting transition consistent with Berezinskii-Kosterlitz-Thouless behavior.
• Measured carrier density of ~7x10^13 cm^-2 at 5 K.
• Estimated superconducting layer thickness of ~8 nm and coherence length of ~30 nm.

Conclusions:

• The interface between LaAlO3 and KTaO3(110) hosts intrinsic two-dimensional superconductivity.
• The observed properties strongly support a Berezinskii-Kosterlitz-Thouless superconducting transition.
• This system offers a novel platform for fundamental research into 2D superconductivity in oxide heterostructures.