Pressure induced metallization of SiH4(H-2)(2) via first-principles calculations

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	Pressure induced metallization of SiH4(H-2)(2) via first-principles calculations
	Y. K. Wei; N. N. Ge; G. F. Ji; X. R. Chen; L. C. Cai; D. Q. Wei
	2014
发表期刊	Computational Materials Science
ISSN	0927-0256
卷号	88 页码:116-123
摘要	Structure of SiH4-H-2, which has attracted much theoretical and experimental effort, but there remains many unsolved problems, for example, behavior of H-2 under compression, as well as the metallization mechanism induced by pressure. In this work, two competitive structures of SiH4(H-2)(2) were studied to find the stable structure in the pressure range of 6.8-35 GPa. Our results indicate that tI18 structure is the possible structure, which can also be viewed as a distorted face-centered-cubic lattice. The absence of imaginary frequency modes for phonon dispersion curves indicates that tI18 structure is dynamically stable in the pressure range of 6.8-35 GPa. The optimized structure is also in good agreement with experimental structure, supported by X-ray diffraction data. Specially, the calculated low-frequency phonon modes and electronic band structure show that this crystal becomes metallic at 190 GPa and 0 K, and the potential superconductivity in this compound can be attributed to a conventional electron-phonon mechanism that couples the low-frequency phonon mode to the sp-like conduction electrons. The electron density difference is also analyzed to have a further comprehension on pressure-induced metallization mechanism of this compound. Contrasting with the general view in the previous studies that the metallization may arise from the interaction of SiH4 and H-2, it is found the interaction between H atoms in SiH4 and H-2 molecules is the main factor, that induces the metallization or even superconductivity of SiH4(H-2)(2) under high pressure. (C) 2014 Elsevier B.V. All rights reserved.
部门归属	[wei, yong kai ; ge, ni na ; ji, guang fu ; cai, ling cang] china acad engn phys, inst fluid phys, natl key lab shock wave & detonat phys, mianyang 621900, peoples r china. [wei, yong kai ; ge, ni na ; chen, xiang rong] sichuan univ, coll phys sci & technol, chengdu 610064, peoples r china. [chen, xiang rong] chinese acad sci, int ctr mat phys, shenyang 110016, peoples r china. [wei, dong qing] shanghai jiao tong univ, state key lab microbial metab, shanghai 200240, peoples r china. [wei, dong qing] shanghai jiao tong univ, coll life sci & biotechnol, shanghai 200240, peoples r china. [wei, dong qing] beijing inst technol, state key lab explos sci & technol, beijing 00081, peoples r china. ; ji, gf (reprint author), china acad engn phys, inst fluid phys, natl key lab shock wave & detonat phys, mianyang 621900, peoples r china. ; cyfjkf@caep.ac.cn
关键词	Structure X-ray Diffraction Data Phonon Dispersion Curves Band Structures Metallization Mechanism 1st Principles Electronic-properties Molecular-hydrogen Phase-stability Superconductivity Gpa Temperature Crystal Methane Silane
URL	查看原文
语种	英语
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/72930
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	Y. K. Wei,N. N. Ge,G. F. Ji,et al. Pressure induced metallization of SiH4(H-2)(2) via first-principles calculations[J]. Computational Materials Science,2014,88:116-123.
APA	Y. K. Wei,N. N. Ge,G. F. Ji,X. R. Chen,L. C. Cai,&D. Q. Wei.(2014).Pressure induced metallization of SiH4(H-2)(2) via first-principles calculations.Computational Materials Science,88,116-123.
MLA	Y. K. Wei,et al."Pressure induced metallization of SiH4(H-2)(2) via first-principles calculations".Computational Materials Science 88(2014):116-123.