Electronic and thermoelectric properties of Fe_2 VAI: The role of defects and disorder

摘要

Using first-principles calculations, we show that Fe_2VAl is an indirect band-gap semiconductor. Our calculations reveal that its semimetallic character (which is sometimes assigned) is not an intrinsic property but originates from magnetic antisite defects and site disorder, which introduce localized in-gap and resonant states changing the electronic properties close to the band gap. These states negatively affect the thermopower S and the power factor equal to S~2σ, decreasing the good thermoelectric performance of intrinsic Fe_2 VAI.