正交晶系
锗
结晶学
材料科学
从头算
结构精修
相(物质)
衍射
六方晶系
粉末衍射
空间组
同步辐射
晶体结构
相变
六角相
X射线晶体学
凝聚态物理
物理
化学
硅
光学
冶金
量子力学
作者
K. Takemura,Ulrich Schwarz,K. Syassen,Michael Hanfland,N. E. Christensen,D. L. Novikov,I. Loa
出处
期刊:Physical review
日期:2000-10-15
卷期号:62 (16): R10603-R10606
被引量:73
标识
DOI:10.1103/physrevb.62.r10603
摘要
Structural phase transitions of germanium at pressures up to 190 GPa have been investigated by means of angle-dispersive x-ray powder diffraction using synchrotron radiation. Near 100 GPa the primitive hexagonal modification of Ge transforms to an orthorhombic phase with 16 atoms per unit cell. The results of full-profile Rietveld refinements in space group $\mathrm{Cmca}$ indicate that the orthorhombic modification of Ge is isotypic to the phase Si-VI. Near 160--180 GPa Ge undergoes a transition to a structure assigned as hexagonal close packed (hcp). Ab initio calculations of pressure-dependent enthalpies and optimized structural parameters are presented for different structures of Ge. The calculated results clearly support the observed occurrence of the $\mathrm{Cmca}$ structure in Ge.
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