Intrinsic Mobility Limiting Mechanisms in Lanthanum-Doped Strontium Titanate

The temperature dependent Hall mobility data from La-doped SrTiO₃ thin films are analyzed and modeled considering various electron scattering mechanisms. We find that a ~6 meV transverse optical phonon 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 and ionized impurity scattering mechanisms, excellent quantitative agreement between mobility measurement and model is achieved in the whole temperature range (2--300 K) and carrier concentrations ranging over a few orders of magnitude (8×10¹⁷ --2×10²⁰ cm^-3).