Stability of high-pressure phases in II-VI semiconductors by a density functional lattice dynamics approach
Stability of high-pressure phases in II-VI semiconductors by a density functional lattice dynamics approach
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DOI：
10.1103/physrevb.75.172103
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发表时间：
2007-05
影响因子：
3.7
通讯作者：
D. Kirin;Igor Lukačević
中科院分区：
文献类型：
--
作者：
D. Kirin;Igor Lukačević
研究了几种II-VI族半导体岩盐结构相对于高压Cmcm结构的稳定性 ZnS、ZnSe、CdS和CdSe.晶格动力学计算表明，相对于布里渊区边界处的横向声学模式，岩盐结构是不稳定的。相变是第二顺序，并与细胞加倍在高压Cmcm阶段与冻结变形。本文的计算方法比传统的公切线法更精确地给出了转捩压力。由于在过渡的体积变化是非常小的或在所有研究的晶体为零，过渡估计从压力的区域边界横向声学模式的频率为零。在结构测量中观察到的相变压力比以前的计算更准确地再现和观察到的和计算的转变压力之间的差异是1%至8%的顺序。
Stability of the rocksalt structure with respect to the high-pressure Cmcm structure was investigated for several II-VI semiconductors ZnS, ZnSe, CdS, and CdSe. The lattice dynamics calculations reveal that the rocksalt structure is unstable with respect to the transversal acoustic mode at the Brillouin zone boundary. The phase transition is of the second order and is associated with cell doubling in the high-pressure Cmcm phase with frozen deformation. The present calculation gives the transition pressure more accurately than the classical method, which uses the common tangent. Since the volume change at the transition is very small or zero in all studied crystals, transitions were estimated from the pressure at which the frequency of the zone boundary transversal acoustic mode goes to zero. The observed pressures of the phase transitions in structural measurements were reproduced more accurately than in previous calculations and the difference between observed and calculated transition pressure is of the order of 1% to 8%.