Predicted Novel High-Pressure Phases of Lithium
Predicted Novel High-Pressure Phases of Lithium
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预测的锂新高压相
DOI：
10.1103/physrevlett.106.015503
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发表时间：
2011-01-07
影响因子：
8.6
通讯作者：
Ma, Yanming
中科院分区：
文献类型：
--
作者：
Lv, Jian;Wang, Yanchao;Ma, Yanming
在高压下，“简单”锂（Li）表现出复杂的结构行为，甚至经历了不寻常的金属到半导体的转变，导致了对致密锂的结构多晶型感兴趣的主题。本文利用新发展的粒子群优化技术预测了两个意想不到的正交高压结构Aba2-40（40个原子/细胞，稳定在60-80 GPa）和Cmca-56（56个原子/细胞，稳定在185-269 GPa）。Aba2-40具有沿b轴堆叠的4原子层和8原子层，是一种在70 GPa时具有明显带隙> 0:8 eV的半导体，这是由于晶体空洞中价电子的核心排出和局域化造成的。我们预测Cmca-56在85-434 GPa的宽压力范围内存在局部三角形平面结构基序，有利于金属丰度较弱。
Under high pressure, "simple" lithium (Li) exhibits complex structural behavior, and even experiences an unusual metal-to-semiconductor transition, leading to topics of interest in the structural polymorphs of dense Li. We here report two unexpected orthorhombic high-pressure structures Aba2-40 (40 atoms/cell, stable at 60-80 GPa) and Cmca-56 (56 atoms/cell, stable at 185-269 GPa), by using a newly developed particle swarm optimization technique on crystal structure prediction. The Aba2-40 having complex 4- and 8-atom layers stacked along the b axis is a semiconductor with a pronounced band gap > 0: 8 eV at 70 GPa originating from the core expulsion and localization of valence electrons in the voids of a crystal. We predict that a local trigonal planar structural motif adopted by Cmca-56 exists in a wide pressure range of 85-434 GPa, favorable for the weak metallicity.