Abstract

This study is devoted to ab initio calculations of the ground state properties of the Mn₂NiGa Heusler alloy in the austenitic and martensitic phases. The calculations were performed using an approach in which exchange correlation effects are taken into account via the generalized and metageneralized gradient approximations. The martensitic phase includes four low symmetry structures: the tetragonal unmodulated and three-, five-, and seven-layer modulated monoclinic structures. It is shown that both approximations predict the martensitic transformation between the cubic austenitic and unmodulated martensitic phases, as well as the presence of modulated structures in the martensitic phase. However, the considered approximations lead to opposite behaviors of the energy of the structures and the modulation amplitude with an increase in the modulation period. Namely, these characteristics increase within the generalized gradient approximation and decrease within the metageneralized gradient approximation.

中文翻译：

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Mn2NiGa 合金调制马氏体组织中的交换相关效应

摘要

本研究致力于从头算计算 Mn _{2的基态特性。}奥氏体和马氏体相中的 NiGa Heusler 合金。使用一种方法进行计算，其中通过广义和元广义梯度近似考虑交换相关效应。马氏体相包括四种低对称结构：四方未调制和三、五和七层调制单斜结构。结果表明，两种近似都预测了立方奥氏体和未调制马氏体相之间的马氏体转变，以及马氏体相中调制结构的存在。然而，所考虑的近似值随着调制周期的增加导致结构能量和调制幅度的相反行为。即，