Hg2CuTi型Mn2NiGe合金的电子结构、磁性对压力、四方变形的响应

运用基于密度泛函理论的第一性原理方法，研究了Hg2CuTi型 Mn2NiGe合金的电子结构对外加压力的响应以及Mn2NiGe的电子结构、磁性对四方变形的响应．结果表明：i）随着外加压力的增加，因Ni、Mn原子间距的减小而导致杂化程度的增强，使得态密度整体向低能区域移动，同时，态密度幅度整体略有减小；ii）在由奥氏体相到马氏体相的变形中，同样因Ni、Mn原子间距的减小而导致杂化程度的增强，占据态的态密度向低能区域移动，体系的能量降低，同时，成键态向低能方向移动，反键态向高能方向移动，能带变宽，成键作用加强，最终导致在马氏体相中的稳定性增大；iii）在四方变形过程中，Mn2NiGe总磁矩的变化主要由Ni原子磁矩的变化所产生．

The response to pressure and tetragonal distortion of electronic structure and magnetism for the Hg2CuTi-type Mn2NiGe alloy

The response to pressure and tetragonal distortion of electronic structure and magnetism for the Hg2CuTi-type Mn2NiGe alloy were studied by first-principles method based on the density functional theory. The study show that: i) The density of states move to lower energy and diminishes in intensity results from the enhanced Ni-Mn atoms hybridization caused by a decrease in the Ni-Mn distance with pressure increase. ii) In the process of transform from the austenite phase to the martensite phase, the system energy will be decreased by the density of states of occupied state move to lower energy and the bonding interaction stronger caused by energy band broader results from the enhanced Ni-Mn atoms hybridization caused by a decrease in the Ni-Mn distance as mentioned already. These are reasons for the stabilization of martensitic phase. iii) In the process of tetragonal distortions, the change of total magnetic moment is to decided by the change of magnetic moment of Ni atom.