Electronic Structure of B2-Type Ti–Ni–Fe Alloys Exhibiting Second-Order-Like Structural Transformation

抄録

We have calculated electronic structure of B2-type Ti–(50−x)Ni–xFe (0≤x≤28) alloys in order to understand the concentration dependence of the phase stability of the B2-type structure in this system. The Fermi surface of each alloy shows a nesting with a sharp peak of generalized susceptibility χ(q) at a nesting vector of q=[ζζ0]2π⁄a. The value of ζ at the peak position decreases linearly as the Fe content increases. On the contrary, the peak height of χ(q) does not change monotonically but shows a maximum value for Ti–44Ni–6Fe alloy. This result is consistent with the experimental results obtained by resistivity and specific heat measurements. In addition, we found that although the χ(q) shows a local maximum near 1⁄3[110]2π⁄a in Ti–44Ni–6Fe alloy, it shows a saddle point near 1⁄3[110]2π⁄a in TiNi.