Thermoelectric properties of the spin-polarized half-metallic ferromagnetic CsTe and RbSe compounds

Abstract

The thermoelectric properties of the spin-polarized half-metallic ferromagnetic CsTe and RbSe compounds are investigated based on the calculated spin-polarized electronic band structures. The calculated spin-polarized electronic band structures show that both compounds exhibit a half-metallic gap of about 0.06 (0.07) eV for CsTe (RbSe). The spin-down channel of both compounds exhibits a density of states at the Fermi level (E_F), N(E_F), and hence a bare electronic specific heat coefficient (γ) which should lead to unusual thermoelectric properties that is attributed to the fact that only the spin-down channel contributes to the states at E_F. Thus, the bands that cross E_F are responsible for the thermoelectric properties and the ones which do not cross E_F will contribute negligibly to the thermoelectric properties. It has been reported that the transport properties are related to the electrons in the system, and these electrons are defined through the Fermi surface, which determines the electrical conductivity therefore, the Fermi surface of the spin-down channels for both compounds are calculated. It has been found that CsTe exhibits a power factor as a function of chemical potential larger than that obtained from RbSe which is attributed to the fact that CsTe possesses much higher electronic electrical conductivity than that of RbSe.