Electronic band structure, magnetic and thermoelectric properties of sodium and lanthanum cobaltites: ab initio PAW approach

Philosophical Magazine. 2025. Vol. 105. No. 18. P. 1114–1138.

Zhukov V., Eugenio V. Chulkov

The electronic band structure and thermoelectric properties of the NaCoO2 and LaCoO3 cobaltites have been studied by the PAW method. The thermoelectric characteristics were calculated on the basis of Boltzmann–Onsager theory taking into account electron scattering by optical phonons, and the thermal conductivity coefficient was calculated using the Slack approximation. For LaCoO3 with electronic conductivity, in accordance with experimental data, the change of sign of Seebeck coefficient is noted at high temperatures. It is shown for NaCoO2 with hole conductivity that the sign of Seebeck coefficient can also be expected to change at high temperature. By varying starting magnetic moments, five solutions compatible with the LaCoO3 semiconductor conductivity were achieved. The magnetic states of cobalt atoms at semiconductor conductivity may have spin value S = 0 or 3/2.

Keywords: Теория функционала плотности, Density functional theory (DFT), Electronic band structure, PAW method, thermoelectric properties, термоэлектрические свойства, sodium cobaltite, lanthanum cobaltite, Электронная зонная структура, кобальтит натрия, кобальтит лантана, Метод PAW