Huang Wen-Chao, Li Xue-Song, Wang Xiao-Fang, Li Yun-Xia
School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, People's Republic of China.
National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, People's Republic of China.
J Phys Condens Matter. 2024 Mar 7;36(22). doi: 10.1088/1361-648X/ad2388.
Based on first-principles calculation of density functional theory, this study investigates the structural stability, magnetic properties, and electronic properties of the three different phases (i.e. type 1, type 2, and type 3) of OsCoSi (=Ti, Zr, Hf) in a new quaternary Heusler alloy series. The corresponding equilibrium lattice constants of each type are optimized, and the change of formation enthalpy and elastic constant phonon spectrum show that the OsCoSi (=Ti, Zr, Hf) alloy is thermodynamically, dynamically and mechanically stable. Furthermore, the bonding features of each phase are discussed. It is found that all type 1 structures of OsCoSi (=Ti, Zr, Hf) exhibit natural half-metallicity (HM) in equilibrium lattice constant, and their equilibrium lattice constants in the ground state were determined to be 5.909 Å for OsTiCoSi, 6.155 Å for OsZrCoSi, and 6.100 Å for OsHfCoSi. Meanwhile, by testing the alloy under different pressures, the range of the integer magnetic moment non-equilibrium lattice constants for the three alloys OsTiCoSi, OsZrCoSi, and OsHfCoSi are 5.710 Å ∼ 6.329 Å, 5.696 Å ∼ 6.1557 Å and 5.716 Å ∼6.1009 Å, respectively, which is wide and is more close to the practical application for spin-polarized materials. In addition, its magnetic moment is consistent with the values given by the Slater-Pauling rule. Furthermore, the forming of the HM gap is examined by analysing the total and partial density of states, energy bands of alloy's electronic property, with respect to the calculated results. What's more, special attention is paid to the differences of the properties for series Heusler alloys. It is found that the electronics properties distinction is mainly based on valence electron changes. However, the lattice constants are susceptible to size of a nucleus.
基于密度泛函理论的第一性原理计算，本研究考察了新型四元赫斯勒合金系列OsCoSi（=Ti、Zr、Hf）三种不同相（即1型、2型和3型）的结构稳定性、磁性和电子性质。对每种类型的相应平衡晶格常数进行了优化，形成焓、弹性常数声子谱的变化表明OsCoSi（=Ti、Zr、Hf）合金在热力学、动力学和力学上是稳定的。此外，还讨论了各相的键合特征。研究发现，OsCoSi（=Ti、Zr、Hf）的所有1型结构在平衡晶格常数下均表现出自然半金属性（HM），其基态平衡晶格常数对于OsTiCoSi为5.909 Å，对于OsZrCoSi为6.155 Å，对于OsHfCoSi为6.100 Å。同时，通过在不同压力下对合金进行测试，三种合金OsTiCoSi、OsZrCoSi和OsHfCoSi的整数磁矩非平衡晶格常数范围分别为5.710 Å ∼ 6.329 Å、5.696 Å ∼ 6.1557 Å和5.716 Å ∼6.1009 Å，该范围较宽且更接近自旋极化材料的实际应用。此外，其磁矩与斯莱特-泡利规则给出的值一致。此外，通过分析合金电子性质的总态密度和分态密度、能带，考察了HM能隙的形成情况，并给出了计算结果。更重要的是，特别关注了系列赫斯勒合金性质的差异。研究发现，电子性质的差异主要基于价电子的变化。然而，晶格常数易受原子核大小的影响。
