Investigation of the electronic and thermoelectric properties of Fe2 ScX (X = P, As and Sb) full Heusler alloys by using first principles calculations

Abstract: By using ab initio electronic structure calculations here we report the three new full Heusler alloys which are possessing very good thermoelectric behavior and expected to be synthesized in the laboratories. These are Fe2 ScP, Fe2 ScAs and Fe2 ScSb compound. First two compounds are indirect band gap semiconductors and the last one shows semimetallic ground state. The value of band gap of Fe2 ScP and Fe2 ScAs is 0.3 and 0.09 eV, respectively. These compounds show the presence of flat conduction bands along {\Gamma} - X-direction suggesting for the large electron like effective mass and promising for very good thermoelectric behavior of the compounds. At 200 K, the Seebeck coefficients of Fe2 ScP, Fe2 ScAs and Fe2 ScSb compounds are -770, -386 and -192{\mu}V/K, respectively. The maximum power factor (P F ) is expected for the n-type doping in these materials. The heavily doped Fe2 ScP and Fe2 ScAs have P F >60 for a wide temperature range, which is comparable to the PF of Bi2 Te3 - a well known and one of the best commercially used thermoelectric material. Present work suggests the possible thermoelectric applicability of these materials in a wide temperature range.