Thickness dependence of the mobility at the LaAlO_3 / SrTiO_3 interface

TL;DR

This study investigates how the electron mobility at LaAlO_3 / SrTiO_3 interfaces varies with LaAlO_3 layer thickness, revealing a critical threshold and significant mobility reduction as thickness increases.

Contribution

It provides systematic analysis of thickness-dependent electronic transport properties at LaAlO_3 / SrTiO_3 interfaces, highlighting a critical thickness and mobility decline.

Findings

Conductivity appears above four unit cells of LaAlO_3.

Mobility decreases nearly two orders of magnitude with increasing thickness.

Sheet resistance and magnetoresistance depend systematically on LaAlO_3 thickness.

Abstract

The electronic transport properties of a series of LaAlO_3 / SrTiO_3 interfaces were investigated, and a systematic thickness dependence of the sheet resistance and magnetoresistance was found for constant growth conditions. This trend occurs above the critical thickness of four unit cells, below which the LaAlO_3 / SrTiO_3 interface is not conducting. A dramatic decrease in mobility of the electron gas of nearly two orders of magnitude was observed with increasing LaAlO_3 thickness from five to 25 unit cells.