On the origin of the heavy-fermion like behavior of the Heusler-type Fe3-xVxM (M = Al, Ga) alloys

Abstract

The electronic structure of I-e:> V., M (M=A1, Ga) alloys was investigated by ab initio method. Magnetic and non-magnetic band structure of !•'(>:» , \ ,M was calculated for concentrations x = 0.0-1.0. Calculations have shown that the transition from magnetic to non-magnetic state is accompanied by the qualitative changes in the band structure in the vicinity of the Fermi level (ef)- For concentrations 0.5 < x < 1 the Density Of States (DOS) at £f in both magnetic states display a sharp peak composed solely of the 3d states of impurity Fe-AS atom ( Fe atom at nominally V atom position of I-eA’Al Heusler compound). In the magnetic state only majority-spin states enter the DOS near £p. The quasi-gap around the ef found in I-'eA’M is filled up by 3df states of Fe-AS which produce the sharp structures at £p. Transition to the non-magnetic state results in the narrowing and strengthening of the peak of Fe-AS 3d-states DOS at £f and the opening of the well-defined gap just above the Fermi level. The changes of the DOS around £f connected with the variation of Fe-AS concentration and magnetic transition explain the peculiar behavior of the electrical resistivity observed experimentally.