Dynamical response and confinement of the electrons at the LaAlO3/SrTiO3 interface

TL;DR

This study uses infrared ellipsometry and transport measurements to analyze the electronic properties at the LaAlO3/SrTiO3 interface, revealing carrier density, effective mass, and confinement profile, indicating polaronic correlations.

Contribution

It provides detailed characterization of the electron dynamics and spatial distribution at the interface, highlighting polaronic effects and asymmetric confinement.

Findings

Sheet carrier density of 5-9x10^13 cm^-2

Effective mass approximately 3 times the electron mass

Asymmetric vertical density profile extending up to 11 nm

Abstract

With infrared ellipsometry and transport measurements we investigated the electrons at the interface between LaAlO3 and SrTiO3. We obtained a sheet carrier density of Ns~5-9x 10E13 cm^-2, an effective mass of m*~3m_e, and a strongly frequency dependent mobility. The latter are similar as in bulk SrTi1-xNbxO3 and therefore suggestive of polaronic correlations of the confined carriers. We also determined the vertical density profile which has a strongly asymmetric shape with a rapid initial decay over the first 2 nm and a pronounced tail that extends to about 11 nm.