Transport and thermoelectric properties of the LaAlO$_3$/SrTiO$_3$ interface

TL;DR

This study investigates the transport and thermoelectric properties of the LaAlO$_3$/SrTiO$_3$ interface, revealing multiple electron channels, band contributions, and magnetic field effects, providing insights into its complex electronic behavior at low temperatures.

Contribution

It presents a comprehensive model describing the temperature dependence of thermoelectric properties and identifies magnetic field-dependent scattering at the LaAlO$_3$/SrTiO$_3$ interface.

Findings

Two electron-like charge carriers are observed above 4.2 K.

A model describing the thermoelectric tensor's temperature dependence is developed.

Magnetic field influences scattering processes at the interface.

Abstract

The transport and thermoelectric properties of the interface between SrTiO$_3$ and a 26-monolayer thick LaAlO$_3$-layer grown at high oxygen-pressure have been investigated at temperatures from 4.2 K to 100 K and in magnetic fields up to 18 T. For $T>$ 4.2 K, two different electron-like charge carriers originating from two electron channels which contribute to transport are observed. We probe the contributions of a degenerate and a non-degenerate band to the thermoelectric power and develop a consistent model to describe the temperature dependence of the thermoelectric tensor. Anomalies in the data point to an additional magnetic field dependent scattering.