Observation of two-dimensional superconductivity at the LaAlO3/KTaO3(110) heterointerface

TL;DR

This paper reports the discovery of two-dimensional superconductivity at the LaAlO3/KTaO3(110) interface, characterized by a transition temperature of 0.9 K, anisotropic critical fields, and Berezinskii-Kosterlitz-Thouless behavior, offering a new platform for studying 2D superconductivity.

Contribution

It demonstrates the existence of 2D superconductivity at the LaAlO3/KTaO3(110) interface, with detailed measurements of its properties and implications for oxide interface research.

Findings

Superconductivity with Tc ~0.9 K observed at the interface.

Superconductivity exhibits large anisotropy and BKT transition.

Superconducting layer thickness ~8 nm, coherence length ~30 nm.

Abstract

We report on the observation of a Tc ~0.9 K superconductivity at the interface between LaAlO3 film and the 5d transition-metal oxide KTaO3(110) single crystal. The interface shows a large anisotropy of the upper critical field, and its superconducting transition is consistent with a Berezinskii-Kosterlitz-Thouless transition. Both facts suggest that the superconductivity is two-dimensional (2D) in nature. The carrier density measured at 5 K is ~7 time 10^13 cm-2. The superconducting layer thickness and coherence length are estimated to be ~8 and ~30 nm, respectively. Our result provides a new platform for the study of 2D superconductivity at oxide interfaces.