High-pressure synthesis of tetragonal iron aluminide FeAl2

摘要

Abstract Tetragonal FeAl2 has been predicted a narrow-gap semiconductor stable at ambient pressure. However, only a complex, triclinic FeAl2 has been experimentally observed. We calculated the stability of tetragonal FeAl2 under various pressures and revealed that tetragonal FeAl2 is more stabilized under high pressure. We successfully synthesized tetragonal FeAl2 at 10GPa and 1873K with diamond-anvil cell techniques. The X-ray diffraction pattern of the sample was unchanged after releasing the pressure; that is, the pressure-induced transformation is irreversible. We also calculated the transport properties of tetragonal FeAl2. The results indicate that tetragonal FeAl2 is a promising candidate for thermoelectric materials. Graphical abstract Display Omitted ]]>