Electronic Structure and Lattice Transformation in Ni₂MnGa and Co₂NbSn

Abstract

It is known experimentally that Heusler alloys, Ni₂MnGa and Co₂NbSn undergo the cubic-to-tetragonal lattice transformation, in a ferromagnetic state and a paramagnetic one, respectively. We calculated electronic structures of Co₂NbSn and Ni₂MnGa for both cubic and tetragonal structures by KKR method. Comparing the density-of-state of the cubic and tetragonal structures for each alloy, it is expected that the band Jahn-Teller effect cause the lattice transformation in both alloys.