High pressure stability of the monosilicides of cobalt and the platinum group elements
High pressure stability of the monosilicides of cobalt and the platinum group elements
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DOI：
10.1016/j.jallcom.2014.11.179
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发表时间：
2015-03
影响因子：
6.2
通讯作者：
J. Hernández;L. Vočadlo;I. Wood
中科院分区：
文献类型：
--
作者：
J. Hernández;L. Vočadlo;I. Wood
采用静态第一性原理计算方法研究了CoSi、RuSi、RhSi、PdSi、OsSi、IrSi和PtSi在300 GPa以下的高压稳定性。实验发现，在大气压下，CoSi、RuSi和OsSi采用立方ε-FeSi结构（P213），而RhSi、PdSi、IrSi和PtSi采用正交MnP结构（Pnma）.在高压下，CoSi、RuSi和OsSi分别在270 GPa、7 GPa和6 GPa下发生了向CsCl结构（Pm 3 <$m）的相变。RhSi和IrSi在10 GPa和25 GPa下转变为ε-FeSi结构。对于PdSi和PtSi，在13 GPa和20 GPa下发生了由MnP结构向四方CuTi结构（P4/nmm）的转变.电子态密度的压力依赖性表明，RuSi和OsSi在ε-FeSi结构中是半导体，而在CsCl结构中变成金属. RhSi和IrSi是MnP结构中的金属，并且以其高压ε-FeSi形式变成半金属。在ε-FeSi构型中CoSi是半金属。PdSi和PtSi在高达300 GPa的压力下保持金属状态。
The high pressure stability of CoSi, RuSi, RhSi, PdSi, OsSi, IrSi and PtSi was investigated by static first-principles calculations up to 300 GPa at 0 K. As found experimentally, at atmospheric pressure, CoSi, RuSi and OsSi were found to adopt the cubic ε-FeSi structure (P 2 1 3) whereas RhSi, PdSi, IrSi and PtSi were found to adopt the orthorhombic MnP (Pnma) structure. At high pressure, CoSi, RuSi and OsSi show a phase transition to the CsCl structure (Pm 3¯ m) structure at 270 GPa, 7 GPa and 6 GPa respectively. RhSi and IrSi were found to transform to an ε-FeSi structure at 10 GPa and 25 GPa. For PdSi and PtSi, a transformation from the MnP structure to the tetragonal CuTi structure (P 4/nmm) occurs at 13 GPa and 20 GPa. The pressure dependence of the electronic density of states reveals that RuSi and OsSi are semiconductors in the ε-FeSi structure and become metallic in the CsCl structure. RhSi and IrSi are metals in the MnP structure and become semimetals in their high pressure ε-FeSi form. CoSi in the ε-FeSi configuration is a semimetal. PdSi and PtSi remain metallic throughout up to 300 GPa.