Soft-phonon instability in zincblende HgSe and HgTe under moderate pressure: Ab initio pseudopotential calculations
Soft-phonon instability in zincblende HgSe and HgTe under moderate pressure: Ab initio pseudopotential calculations
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DOI：
10.1103/physrevb.80.144110
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发表时间：
2009-10
影响因子：
3.7
通讯作者：
S. Radescu;A. Mujica;R. Needs
中科院分区：
文献类型：
--
作者：
S. Radescu;A. Mujica;R. Needs
汞硫属化合物HgSe和HgTe在适度压缩下表现出特殊的行为，如观察到从常压锌闪锌矿相到具有空间群C2221的正方晶亚稳相的“隐藏”转变。本文在密度泛函理论的框架下，对HgSe和HgTe的低压锌闪锌矿相的稳定性和向C2221结构的转变进行了从头算伪势研究。我们将C2221相的观察结果与这些材料的锌闪锌矿相的横向声子分支的不稳定性联系起来。我们详细研究了锌闪锌矿→C2221相变的机理以及C2221相在压力作用下的结构演化。
The mercury chalcogenides HgSe and HgTe show peculiar behavior under moderate compression such as the unusual observation of a “hidden” transition from their ambient-pressure zincblende phase to an orthorhombic metastable phase with space group C2221. We present here the results of an ab initio pseudopotential study within the framework of the density-functional theory of the stability of the low-pressure zincblende phases of HgSe and HgTe and the transition to the C2221 structure. We relate the observation of the C2221 phase to an instability in the transverse-acoustic phonon branches of the zincblende phases of these materials. We have studied in detail the mechanism of the zincblende→C2221 transition as well as the structural evolution of the C2221 phase under pressure.