First-Principles Calculations on the Structural Phase Transition, Magnetism, Half-Metallicity and Electronic Properties of CoOsCrGe

哈斯勒合金是一类极具特色的多元多结构金属间化合物，而具有铁磁半金属特性的哈斯勒合金凭借在自旋电子学领域展现出独特的优势，成为自旋电子器件的关键材料。本研究聚焦新型四元哈斯勒合金CoOsCrGe，系统探究其相变特性与半金属行为。研究发现，CoOsCrGe合金在立方相状态下呈现显著半金属特性。同时，该合金的四方相与立方相存在较大的能量差值，且四方畸变程度达1.32，为马氏体相变的发生提供了条件。除此之外，CoOsCrGe合金的居里温度高达996.48 K，远超室温环境要求。CoOsCrGe优异的特性使其有望成为性能突出的新型功能材料。本研究成果为开发新型功能材料，提供了坚实的理论设计依据。Heusler alloys are a kind of multi-element and multi-structural intermetallic compounds with distinctive features. The Heusler alloys with ferromagnetic half-metallic properties have shown unique advantages in the field of spintronics and thus become the key materials for spintronic devices. This research focuses on the novel quaternary Heusler alloy CoOsCrGe and systematically explores its phase transition characteristics and half-metallic behavior. It is found that the CoOsCrGe alloy exhibits remarkable half-metallic properties in the cubic phase state. Meanwhile, there is a large energy difference between the tetragonal phase and the cubic phase of this alloy, and the degree of tetragonal distortion reaches 1.32, which provides conditions for the occurrence of martensitic phase transition. Besides, the Curie temperature of the CoOsCrGe alloy is as high as 996.48 K, far exceeding the requirements of room temperature environment. The excellent properties of CoOsCrGe make it expected to become a new functional material with outstanding performance. The results of this research provide a solid theoretical design basis for the development of new functional materials.