Electronic, optical and thermoelectric properties of Fe₂ZrP compound determined <i>via</i> first-principles calculations

Abstract

In this study, based on the density functional theory and semi-classical Boltzmann transport theory, we investigated the structural, thermoelectric, optical and phononic properties of the Fe₂ZrP compound. The results of the electronic band structure analysis indicate that Fe₂ZrP is an indirect band gap semiconductor in the spin-down state with the band gap of 0.48 eV. Thermoelectric properties in the temperature range of 300-800 K were calculated. Fe₂ZrP exhibits the high Seebeck coefficient of 512 μV K^-1 at room temperature along with the huge power factor of 19.21 × 10¹¹ W m^-1 K^-2 s^-1 at 800 K, suggesting Fe₂ZrP as a potential thermoelectric material. The Seebeck coefficient decreased with an increase in temperature, and the highest value was obtained for p-type doped Fe₂ZrP when the optimum carrier concentration was 0.22 × 10²³ cm^-3; the n-type doped Fe₂ZrP had high electrical conductivity than the p-type doped Fe₂ZrP. Thermal conductivity increased with an increase in chemical potential. Optical calculations illustrated that there was a threshold in the imaginary dielectric function for the spin-down channel. Spin-dependent optical calculations showed that the intraband contributions affected only the spin-up optical spectra due to the free-electron effects. Generally, the results confirmed that the intraband contribution had the main role in the optical spectra in the low energy infra-red and visible ranges of light. We also presented the phononic properties and found that these materials were dynamically stable.