Effect of Al doping on the electronic structure of Fe2VSi

Complete text of publication follows. It has been reported that the structural, thermal and electronic properties of the Heusler-type compound Fe2VSi can be markedly modified by partially substituting Si with Al. The variations of the physical properties are related to the change in the electronic structure due to the hetero-valence doping of Al for Si. We have performed x-ray absorption near edge structure (XANES) study on a series of polycrystalline Fe2VSi1-xAlx (x=0∼0.25) samples to study the electronic structure of these materials. Our Fe K-edge and V K-edge XANES results indicate that the Al doping does not affect the valence of Fe or V, neither has it affected the degree of hybridization between Fe and V. Alternatively, the Al 3p-Fe 3d, and Al 3p-V 3d hybridizations are highly affected by the doping level. From Fe L2,3-edge XANES results we observe a systematic variation on the Fe d unoccupied states, which is correlated with the reported resistivity and thermal power measurements. This work is financially sponsored by National Science Council of Republic of China under grand number NSC 97-2112-M-032-005-MY3.