Possible Martensitic Transformation in Heusler Alloy Pt2MnSn from First Principles**Supported by the National Natural Science Foundation of China under Grant Nos 51301119, 51301195, 51171206 and 51401140, the National Science Foundation for Young Scientists of Shanxi Province under Grant No 2013021010-1, and the Youth Foundation of Taiyuan University of Technology under Grant No 1205-04020102.

Abstract

Using density functional theory calculations, we investigate the tetragonal distortion, electronic structure and magnetic property of Pt2MnSn. The results indicate that, when the volume-conserving tetragonal distortion occurs, the energy minimum appears at c/a = 0.84, and the energy difference between the minimum and cubic phase is as high as 107 meV/f.u. Thus from the point of view of thermodynamics, martensitic transformation may occur in Pt2MnSn with decreasing the temperature. The electronic structure of its cubic and martensitic phases also approves this. Moreover, both the cubic and tetragonal phases of Pt2MnSn are ferromagnetic structures and their total magnetic moments are 4.26 μB and 4.12 μB, respectively.