Thermoelectric properties of Fe2VAl in the temperature range 300–800 K: A combined experimental and theoretical study

Abstract

Here, the experimentally observed thermoelectric (TE) properties of Fe2VAl are understood through electronic structure calculations in the temperature range of 300–800 K. The Seebeck coefficient (S) is observed as ∼−138μV/K at 300 K. Then, the |S| decreases with increase in temperature, with a value of ∼−18μV/K at 800 K. The temperature dependence of electrical conductivity, σ (thermal conductivity, κ) exhibits the increasing (decreasing) trend with values of ∼1.2× 105Ω−1 m−1 (∼23.7 W/m K) and ∼2.2× 105Ω−1 m−1 (∼15.3 W/m K) at 300 K and 800 K, respectively. In order to understand these transport properties, the DFT based semi-classical Boltzmann theory is used. The contributions of multi-band electron and hole pockets are found to be mainly responsible for the temperature dependent trend of these properties. The present study suggests that DFT based calculations provide reasonably good explanations of experimental TE properties of Fe2VAl in the high-temperature range of 300–800 K.