2008/08/13 by Wilfried Wunderlich, Wunderlich, Wilfried, Hiromichi Ohta +3
Materials Science · Physics and Astronomy · #Advanced Thermoelectric Materials and Devices #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.0808.1772
7 pages, 6 figures
arxiv created 2008/08/13 · openalex publication_date 2008/08/13 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The effective mass is one of the main factors for enlarging the Seebeck coefficient and electronic conductivity of SrTiO3-based thermoelectric materials [1,2]. The goal of this paper is to clarify, how superlattices can change the effective mass and other features of the bandstructure. The natural Ruddlesden-Popper phase (SrTiO3)n(SrO)m with n=2, m=1 the situation changes, because the TiO6-octahedrons are slightly extended, due to diluted density of the SrO layer. Another effect is the deformed electron density, which leads to reduced effective mass perpendicular to the layer, but enlarged parallel to the plane [3]. The average value of the effective mass over this anisotropy of the 2-dimensional electron gas (2DEG) for pure Ruddlesden-Popper phases is smaller, but can increase beyond the value of pure Pervoskite for certain doping elements. In the same way, artificial superlattices (SrTiO3)x/(SrTi1-z(Nb)zO3)y were examined. When fine nanostructures (n=2, m=3 or n=3, m=2) are present the effective mass increases, when the structure becomes coarser (n=4, m=1) smaller values are determined.