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Updated: Apr 15, 2026
Synthesis of Non-uniformly Pr-doped SrTiO3 Ceramics and Their Thermoelectric Properties
Published on: August 15, 2015
Dopant incorporation site in sodium cobaltate's host lattice: a critical factor for thermoelectric performance
M H N Assadi1, H Katayama-Yoshida
1Department of Materials Physics, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan.
Abstract:
NaxCoO2 that comprises alternating Na and CoO layers has exotic magnetic and thermoelectric properties that could favorably be manipulated by adding dopants or varying Na concentration. In this work, we investigated the structural and electronic properties of Sr and Sb doped NaxCoO2 (x = 0.50, 0.625, 0.75 and 0.875) through comprehensive density functional calculations. We found that Sr dopants always occupy a site in the Na layer while Sb dopants always substitute a Co ion in the host lattice regardless of Na concentration. This conclusion withstood when either generalized gradient approximation (GGA) or GGA + U method was used. By residing on the Na layer, Sr dopants create charge and mass inertia against the liquid-like Na layer and, therefore, improve the crystallinity and decrease the electrical resistivity through better carrier mobility. On the other hand, by substituting Co ions, Sb dopants reduce the electrical conductivity and therefore decrease the Seebeck coefficient.
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