Polaron transport and thermoelectric behavior in La-doped SrTiO3 thin films with elemental vacancies

Abstract

Electrodynamic properties of La-doped SrTiO3 thin films with controlled elemental vacancies have been investigated using optical spectroscopy and thermopower measurement. In particular, we observed a correlation between the polaron formation and thermoelectric properties of the transition metal oxide (TMO) thin films. With decreasing oxygen partial pressure during the film growth (P(O2)), a systematic lattice expansion was observed along with the increased elemental vacancy and carrier density, experimentally determined using optical spectroscopy. Moreover, we observed an absorption in the mid-infrared photon energy range, which is attributed to the polaron formation in the doped SrTiO3 system. Thermopower of the La-doped SrTiO3 thin films could be largely modulated from -120 to -260 μV K-1, reflecting an enhanced polaronic mass of ~3 < mpolron/m < ~4. The elemental vacancies generated in the TMO films grown at various P(O2) influences the global polaronic transport, which governs the charge transport behavior, including the thermoelectric properties.

arXiv comment18 pages including 5 figures

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Cited by in corpus (6)

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• Thermoelectric La-doped SrTiO3 epitaxial layers with single-crystal quality: from nanometer to micrometer and mosaicity effects
• Unified modelling of the thermoelectric properties in SrTiO3
• Band-selective Plasmonic Polaron in Thermoelectric Semimetal Ta${}_2$PdSe${}_6$ with ultra-high power factor
• Electronic Structure and Thermoelectric Properties of Half-Heusler Alloys NiTZ