Pseudogap Formation in the Intermetallic Compounds (Fe1 - xVx)Al

Optical conductivity data of the intermetallic compounds (Fe1 - xVx)3Al (0 ? x ? 0.33) reveal that their density of states around the Fermi energy (EF) is strongly reduced as x is increased. In particular, Fe2VAl (x = 0.33) has a deep, well-developed pseudogap of 0.1-0.2 eV at EF and a small density (?5 × 1020 cm-3) of carriers, which is highly unusual for intermetallic compounds. It is shown that the pseudogap results from the band structure of Fe2VAl, rather than from temperature-dependent correlation effects. Based on the present results, we propose a simple model that consistently explains both the semiconductorlike transport and the metallic photoemission results previously observed for Fe2VAl