Hall mobility in strontium titanate at high temperatures

Abstract

We report on an experimental investigation of Hall mobility in the polar semiconductor SrTiO 3 , in the temperature range where thermal energies are comparable to the energies of the interacting phonon modes. We find, for all crystals measured, i.e. for charge densities from 9.6 × 10 20 cm −3 to 4.1 × 10 17 cm −3 , a mobility decreasing with an increase in temperature for 300 K < T < 650 K, from ~5 cm 2 V −1 s −1 at room temperature to ~1.5 cm 2 V −1 s −1 at 650 K. A slight dependence of mobility on charge density is observed, in that the crystals with higher charge density have the higher mobility. Finally, we interpret our results in terms of existing large polaron transport theory.