Thermoelectric and phononic properties of (Gd, Tb) MnO3 compounds: DFT calculations

Abstract

We have investigated the structural, electronic, magnetic, phononic and thermoelectric properties of rare earth multiferroic manganite RMnO3 (R = Gd and Tb) compounds by the density functional theory within the spin polarized GGA, LDA and mBJ + U + SOC. The full-potential linearized augmented plane wave and pseudopotential methods are used. The combined mBJ + U + SOC study indicates that the obtained results for the band gap are in close agreement with the experimental results. The Bader analysis show that the ionic nature of the MnO bonds cause the large charge transfer from Mn to O atoms. Obtained band gaps are different for two spin channels therefore we have calculated the spin polarization dependence of transport properties. The directional thermoelectric study shows that these compounds are anisotropic. We have also presented the phononical properties such as Raman spectra and Born effective charges.