One-Dimensional Nature of Pairing and Superconductivity at the LaAlO$_3$/SrTiO$_3$ Interface

TL;DR

This study reveals that superconductivity at the LaAlO$_3$/SrTiO$_3$ interface is inherently one-dimensional, with pairing occurring at the boundaries of channels and independent of their width, providing new insights into the pairing mechanism.

Contribution

It demonstrates the intrinsic 1D nature of superconductivity at the interface and shows that pairing occurs at the channel boundaries, not within the interior.

Findings

Superconducting critical current is independent of channel width.

Electron pairing signatures are also independent of channel width.

Superconductivity is confined to the boundary regions of the channels.

Abstract

We examine superconductivity in LaAlO$_3$/SrTiO$_3$ channels in which the channel width transitions from the 1D to 2D regime. The superconducting critical current is independent of the channel width and increases approximately linearly with the number of parallel channels. Signatures of electron pairing outside of the superconducting phase are also independent of channel width. Collectively, these results indicate that electron pairing and superconductivity exist at the boundary of these channels and are absent within the interior region of the channels. The intrinsic 1D nature of superconductivity at the LaAlO$_3$/SrTiO$_3$ interface imposes strong physical constraints on possible electron pairing mechanisms.