Lattice Dynamics and Thermodynamics of Molybdenum from First-Principles Calculations

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	Lattice Dynamics and Thermodynamics of Molybdenum from First-Principles Calculations
	Z. Y. Zeng; C. E. Hu; L. C. Cai; X. R. Chen; F. Q. Jing
	2010
发表期刊	Journal of Physical Chemistry B
ISSN	1520-6106
卷号	114 期号:1 页码:298-310
摘要	We calculated the phase transition, elastic constants, full phonon dispersion Curves, and thermal properties of molybdenum (Mo) for a wide range of pressures using density functional theory. Mo is stable in the body-centered-cubic (bcc) structure up to 703 +/- 19 GPa and then transforms to the face-centered close-packed (fcc) structure at zero temperature, Under high temperature and pressure, the fcc phase of Mo is more stable than the bcc phase. The calculated phonon dispersion Curves accord excellently with experiments. Under pressure, we Captured a large softening along H-P in the TA branches. When the volume is compressed to 7.69 angstrom(3), the frequencies along H-P in the TA branches soften to imaginary frequencies, indicating a Structural instability. When the pressure increases, the phonon calculations oil the fee Mo predict the stability by promoting the frequencies along Gamma to X and Gamma to L symmetry lines from imaginary to real. The thermal equation of state was also investigated. From the thermal expansion coefficient and the heat capacity, we found that the quasiharmonic approximation was valid only up to about melting point at zero pressure. However, under pressure, the validity call be extended to a Much higher temperature.
部门归属	[zeng, zhao-yi; hu, cui-e; chen, xiang-rong; jing, fu-qian] sichuan univ, coll phys sci & technol, chengdu 610064, peoples r china. [zeng, zhao-yi; hu, cui-e; cai, ling-cang; jing, fu-qian] chinese acad sci, inst fluid phys, natl key lab shock wave & detonat phys res, mianyang 621900, peoples r china. [chen, xiang-rong] chinese acad sci, int ctr mat phys, shenyang 110016, peoples r china.;zeng, zy (reprint author), sichuan univ, coll phys sci & technol, chengdu 610064, peoples r china;zhaoyizeng@126.com xrchen@126.com
关键词	X-ray-diffraction State Shock Hugoniots Bcc Transition-metals Equation-of-state Temperature-dependence Elastic-constants Phase-transitions High-pressures Mo Compression
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WOS记录号	WOS:000273404500035
引用统计	被引频次：41[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/31677
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	Z. Y. Zeng,C. E. Hu,L. C. Cai,et al. Lattice Dynamics and Thermodynamics of Molybdenum from First-Principles Calculations[J]. Journal of Physical Chemistry B,2010,114(1):298-310.
APA	Z. Y. Zeng,C. E. Hu,L. C. Cai,X. R. Chen,&F. Q. Jing.(2010).Lattice Dynamics and Thermodynamics of Molybdenum from First-Principles Calculations.Journal of Physical Chemistry B,114(1),298-310.
MLA	Z. Y. Zeng,et al."Lattice Dynamics and Thermodynamics of Molybdenum from First-Principles Calculations".Journal of Physical Chemistry B 114.1(2010):298-310.