Micrometer-scale ballistic transport of electron pairs in LaAlO3/SrTiO3 nanowires

TL;DR

This paper demonstrates micrometer-scale ballistic transport of electron pairs in LaAlO3/SrTiO3 nanowires, revealing quantum interference effects and phase transitions in strongly correlated electron systems.

Contribution

It provides the first evidence of ballistic electron pair transport over micrometer distances in oxide nanowires, extending understanding of quantum transport in correlated materials.

Findings

Observation of Fabry-Perot-like interference in paired phase

Detection of conductance oscillations in the superconducting regime

Unbinding of electron pairs at a critical magnetic field

Abstract

High-mobility complex-oxide heterostructures and nanostructures offer new opportunities for extending the paradigm of quantum transport beyond the realm of traditional III-V or carbon-based materials. Recent quantum transport investigations with LaAlO$_3$/SrTiO$_3$-based quantum dots have revealed the existence of a strongly correlated phase in which electrons form spin-singlet pairs without becoming superconducting. Here we report evidence for micrometer-scale ballistic transport of electron pairs in quasi-one-dimensional (quasi-1D) LaAlO$_3$/SrTiO$_3$ nanowire cavities. In the paired phase, Fabry-Perot-like quantum interference is observed, in sync with conductance oscillations observed in the superconducting regime (at zero magnetic field). Above a critical magnetic field $B_p$, electron pairs unbind and conductance oscillations shift with magnetic field. These experimental observations extend the regime of ballistic electronic transport to strongly correlated phases.