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arXiv 1208.1391cond-mat.mtrl-sci
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$Mo_3Al_2C$相稳定性、振动和电子性质的密度泛函理论研究

Density functional theory study of phase stability, vibrational and electronic properties of $Mo_3Al_2C$

D. Reith, C. Blaas-Schenner, R. Podloucky

摘要:

本文用密度泛函理论研究了β-Mn型($P4_{1}32$)非中心对称超导体Mo_3Al_2C。特别是,它的晶体学和动力学稳定性进行了研究,通过计算晶格振动的谐波近似。研究发现,完全化学计量的化合物是动态不稳定的。然而,具有碳空位的化合物,即,Mo_3Al_2 C_{1-x},当空位浓度x > 0.09时可动态稳定。通过一个简单的热力学模型,我们估算了在实验制备温度下Mo_3Al_2 C_{1-x}的x ~ 0.13-0.14。研究了碳空位浓度对电子结构的影响。

英文摘要:

Based on density functional theory the noncentrosymmetric superconductor Mo_3Al_2C in its well established β-Mn type ($P4_{1}32$) crystal structure is investigated. In particular, its thermodynamical and dynamical stabilities are studied by calculating lattice vibrations within the harmonic approximation. It is found that the fully stoichiometric compound is dynamically unstable. However, compounds with carbon vacancies, i.e., Mo_3Al_2C_{1-x}, can be dynamically stabilized for vacancy concentrations x > 0.09. By means of a simple thermodynamical model we estimate x ~ 0.13-0.14 for Mo_3Al_2C_{1-x} at the experimental preparation temperatures. The influence of the carbon vacancy concentration on the electronic structure is investigated.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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