Two-Dimensional Superconductivity at the LaAlO3/KTaO3 (110) Heterointerface

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 ∼7×1013 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.