Thermoelectric properties of the unfilled skutteruditeFeSb3from first principles and Seebeck local probes

Abstract

Using a combination of first-principles calculations and experimental transport measurements, we study the electronic and magnetic structure of the unfilled skutterudite ${\mathrm{FeSb}}_{3}$. We employ the hybrid functional approach for exchange correlation. The ground state is determined to be antiferromagnetic with an atomic magnetic moment of $1.6\phantom{\rule{0.28em}{0ex}}{\ensuremath{\mu}}_{B}/\mathrm{Fe}$. The N\'eel temperature ${T}_{N}$ is estimated at 6 K, in agreement with experiments which found a paramagnetic state down to 10 K. The ground state is semiconducting, with a small electronic gap of $33\phantom{\rule{0.28em}{0ex}}\mathrm{meV}$, also consistent with previous experiments on films. Charge carrier concentrations are estimated from Hall resistance measurements. The Seebeck coefficient is measured and mapped using a scanning probe at room temperature that yields an average value of $38.6\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{V}\phantom{\rule{0.28em}{0ex}}{\mathrm{K}}^{\ensuremath{-}1}$, slightly lower than the theoretical result. The theoretical conductivity is analyzed as a function of temperature and concentration of charge carriers.