Inhomogeneous superconductivity and quasilinear magnetoresistance at amorphous LaTiO3/SrTiO3 interfaces

TL;DR

This study investigates amorphous LaTiO3/SrTiO3 interfaces, revealing conducting, superconducting, and inhomogeneous electronic properties with quasilinear magnetoresistance, despite the amorphous structure.

Contribution

It demonstrates that amorphous LaTiO3/SrTiO3 interfaces can host 2D electron gases and superconductivity, with spatial electronic fluctuations affecting magnetoresistance.

Findings

Conductivity mainly on SrTiO3 side with 2D electron gas characteristics.

Presence of superconductivity in amorphous heterostructures.

Observation of quasilinear out-of-plane magnetoresistance.

Abstract

We have studied the transport properties of LaTiO3/SrTiO3 (LTO/STO) heterostructures. In spite of 2D growth observed in reflection high energy electron diffraction, Transmission Electron Microscopy images revealed that the samples tend to amorphize. Still, we observe that the structures are conducting, and some of them exhibit high conductance and/or superconductivity. We established that conductivity arises mainly on the STO side of the interface, and shows all the signs of the 2-dimensional electron gas usually observed at interfaces between SrTiO3 and LaTiO3 or LaAlO3, including the presence of two electron bands and tunability with a gate voltage. Analysis of magnetoresistance (MR) and superconductivity indicates presence of a spatial fluctuations of the electronic properties in our samples. That can explain the observed quasilinear out-of-plane MR, as well as various features of the in-plane MR and the observed superconductivity.