Thermopower in quantum confined La-doped SrTiO3 epitaxial heterostructures

We characterize effects of dimensionality reduction and electron confinement on thermopower in La-doped SrTiO3 (LSTO) thin films using hetero-epitaxial capping layers with known conduction band offsets. Hall measurements on SrZrO3/LSTO/(La0.3Sr0.7)(Al0.65Ta0.35)O3 quantum well structures indicate carriers are homogeneously confined in the LSTO film, leading to an unambiguous well width. We do not observe a substantial enhancement of the Seebeck coefficient (S) for confinement widths as thin as 8 A. Recent work towards elucidating the role of thickness scaling on S in complex oxides and implications of our results for using 2D electron confinement to develop advanced thermoelectric materials are discussed.