Theoretical Study of Thermopower Behavior of LaFeO${}_3$ Compound in High Temperature Region

Abstract

The electronic structure and thermopower ($\alpha$) behavior of LaFeO${}_3$ compound were investigated by combining the ab-initio electronic structures and Boltzmann transport calculations. LSDA plus Hubbard U (U = 5 eV) calculation on G-type anti-ferromagnetic (AFM) configuration gives an energy gap of $\sim$2 eV, which is very close to the experimentally reported energy gap. The calculated values of effective mass of holes (m${}^{\ast }$${}_h$) in valance band (VB) are found $\sim$4 times that of the effective mass of electrons (m${}^{\ast }$${}_e$) in conduction band (CB). The large effective masses of holes are responsible for the large and positive thermopower exhibited by this compound. The calculated values of $\alpha$ using BoltzTraP code are found to be large and positive in the 300-1200 K temperature range, which is in agreement with the experimentally reported data.

4 pages, 3 figures, 1 table