Intrinsic Mobility Limiting Mechanisms in Lanthanum-doped Strontium Titanate

TL;DR

This study analyzes the temperature-dependent Hall mobility in La-doped SrTiO3 thin films, identifying key phonon scattering mechanisms that limit electron mobility across a broad temperature and doping range.

Contribution

It introduces a comprehensive model including a ~6 meV TO phonon scattering mechanism, improving understanding of mobility limitations in SrTiO3.

Findings

TO phonon scattering explains mobility dependence from 10-200 K.

Acoustic phonon scattering limits low-temperature mobility.

Model matches experimental data across wide temperature and doping ranges.

Abstract

The temperature dependent Hall mobility data from La-doped SrTiO3 thin films has been analyzed and modeled considering various electron scattering mechanisms. We find that a ~6 meV transverse optical phonon (TO) deformation potential scattering mechanism is necessary to explain the dependence of transport on temperature between 10-200 K. Also, we find that the low temperature electron mobility in intrinsic (nominally undoped) SrTiO3 is limited by acoustic phonon scattering. Adding the above two scattering mechanisms to longitudinal optical phonon (LO) and ionized impurity scattering mechanisms, excellent quantitative agreement between mobility measurement and model is achieved in the whole temperature range (2-300K) and carrier concentrations ranging over a few orders of magnitude (8x1017 cm-3 - 2x1020 cm-3).