Half‐metallicity, magnetism, mechanical, thermal, and phonon properties of FeCrTe and FeCrSe half‐Heusler alloys under pressure,International Journal of Quantum Chemistry

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Half‐metallicity, magnetism, mechanical, thermal, and phonon properties of FeCrTe and FeCrSe half‐Heusler alloys under pressure
International Journal of Quantum Chemistry ( IF 2.3 ) Pub Date : 2020-08-25 , DOI: 10.1002/qua.26417
Ramesh Paudel _{1,

2} , Gopi Chandra Kaphle ₃ , Mohammed Batouche ₄ , Jingchuan Zhu ₅

Affiliation

The half‐metallicity of Heusler alloys is quite sensitive to high pressure and disorder. To understand this phenomenon better, we systematically studied the half‐metallic nature, magnetism, phonon, and thermomechanical properties of FeCrTe and FeCrSe Heusler alloys under high pressure using ab initio calculations based on density functional theory. The ground‐state lattice constants for FeCrTe and FeCrSe alloys are 5.93 and 5.57 Å, respectively, consistent with available theoretical results. Formation energy, cohesive energy, elastic constants, and phonon dispersion confirmed that both compounds are thermodynamically and mechanically stable. The FeCrTe and FeCrSe alloys showed a half‐metallic character with a band gap of 0.68 and 0.58 eV at 0 GPa pressure, respectively, and magnetic moments of 2.01 μ_B for both alloys, using generalized gradient approximation (GGA) approximation. FeCrTe alloy changes from metallic to half‐metallic above 30 GPa pressure using GGA + U. The elastic properties were scrutinized, and it was found that, at 0 GPa pressure, FeCrTe is ductile, and FeCrSe is brittle. Under pressure, FeCrSe becomes brittle above 10 GPa pressure. Average sound velocity V_m, Debye temperature Ɵ_D, and heat capacity C_V were predicted under pressure. These outcomes will improve the integration of Fe‐based half‐Heusler alloys in spintronic devices.

中文翻译：

FeCrTe和FeCrSe半霍斯勒合金在压力下的半金属，磁性，机械，热和声子性能

Heusler合金的半金属性对高压和无序非常敏感。为了更好地理解该现象，我们使用基于密度泛函理论的从头算术系统地研究了FeCrTe和FeCrSe Heusler合金在高压下的半金属性质，磁性，声子和热机械性能。FeCrTe和FeCrSe合金的基态晶格常数分别为5.93和5.57Å，与可用的理论结果一致。形成能，内聚能，弹性常数和声子分散证实了这两种化合物在热力学和机械上均稳定。的FeCrTe和FeCrSe合金表现出半金属特性具有0.68的带隙，并在0 GPA压力，分别0.58电子伏特，和2.01的磁矩 μ_乙对于两种合金，都使用广义梯度近似（GGA）近似。使用GGA + U在高于30 GPa的压力下，FeCrTe合金从金属变为半金属。仔细研究了弹性，发现在0 GPa的压力下，FeCrTe是易延展的，而FeCrSe是脆性的。在压力下，FeCrSe在10 GPa压力以上会变脆。平均声速V_米，德拜温度Ɵ _d，和热容量C ^ _V在压力下预测。这些成果将改善自旋电子器件中铁基半霍斯勒合金的集成度。

更新日期：2020-08-25

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