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Enhanced effective mass in doped SrTiO3 and related perovskites

Wilfried Wunderlich·Hiromichi Ohta·Kunihito Koumoto
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Abstract

The effective mass is one of the main factors determining the Seebeck coefficient and electronic conductivity. Nb-doping increases the effective mass because of two reasons, lattice constants increase and electronic effects. In this ab-initio study the effective mass is estimated from the curvature of electronic bands and it could be clarified that the deformation of SrTiO3 crystals has a significant influence on bandgap and effective DOS and band mass, which are both in excellent agreement to experimental data. However, the electronic effect due to the e2g- band flattening near the Gamma-point due to Nb-doping up to 0.2 at% is the main factor for the increase of effective mass. Doping of La shows a linear decrease of the effective mass; this is explained by the different surrounding of A- and B-site. Substitution of other elements like Ba on the A-site and V on the B-site in SrTiO3 were also found to increase the effective mass.

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Wilfried Wunderlich, Hiromichi Ohta, Kunihito Koumoto. 2009-04-21. Enhanced effective mass in doped SrTiO3 and related perovskites. https://doi.org/10.1016/j.physb.2009.04.012

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