Structural, electronic, elastic and thermal properties of Mg2Si
Structural, electronic, elastic and thermal properties of Mg2Si
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DOI：
10.1016/j.jpcs.2010.01.017
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发表时间：
2010-05
影响因子：
4
通讯作者：
Ben-hai Yu;Dong Chen;Qingbin Tang;Chunlei Wang;D. Shi
中科院分区：
文献类型：
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作者：
Ben-hai Yu;Dong Chen;Qingbin Tang;Chunlei Wang;D. Shi
报道了Mg_2Si的晶格常数、电子密度图、态密度和弹性常数的第一性原理计算结果。晶格参数被发现从实验数据相差小于0.8%。态密度和电子密度图的计算也被用来描述轨道混合和化学键的性质。我们的研究结果表明，在Mg 2Si晶体中的键合相互作用是共价比离子。准谐波德拜模型，通过总能量与体积的计算与平面波赝势方法获得的装置，被应用于研究的弹性，热和振动效应。系统地研究了在0- 1300 K温度区间内，体积弹性模量、Grüneisen参数、德拜温度、热容Cv、Cp和熵随压力P的变化。在高压和高温下观察到性能的显着差异。当T<1300 K时，计算的熵和热容与实验数据符合较好。因此，本研究结果表明，第一性原理和准谐波德拜模型的结合是一种有效的方法来模拟Mg 2Si的行为。
First-principles calculations of the lattice parameter, electron density maps, density of states and elastic constants of Mg2Si are reported. The lattice parameter is found to differ by less than 0.8% from the experimental data. Calculations of density of states and electron density maps are also performed to describe the orbital mixing and the nature of chemical bonding. Our results indicate that the bonding interactions in the Mg2Si crystal are more covalent than ionic. The quasi-harmonic Debye model, by means of total energy versus volume calculations obtained with the plane-wave pseudopotential method, is applied to study the elastic, thermal and vibrational effects. The variations of bulk modulus, Grüneisen parameter, Debye temperature, heat capacity Cv, Cpand entropy with pressure P up to 7GPa in the temperature interval 0–1300K have been systemically investigated. Significant differences in properties are observed at high pressure and high temperature. When T<1300K, the calculated entropy and heat capacity agree reasonably with available experimental data. Therefore, the present results indicate that the combination of first-principles and quasi-harmonic Debye model is an efficient approach to simulate the behavior of Mg2Si.