论文标题
ge $ _ {136} $ type-ii杂质作为亚稳态锗多晶型物合成的前体：一项计算研究
Ge$_{136}$ type-II clathrate as precursor for the synthesis of metastable germanium polymorphs: a computational study
论文作者
论文摘要
在不同温度和压力下，通过\ textit {ab intib}小细胞元动力学对围层II结构GE（CF136）的压缩的响应进行了研究。在较低的压力下，$ p $ = 2.5 GPA亚稳态的金属BCT-5相与$β$ -SN GE（TI4）竞争，该$β$ -SN GE（TI4）以较高的压力形成。在降低温度下，从GE $ _ {136} $获得的无定形中间体的存在更为明显，并且对金属BCT-5可以形成的浓缩结构基序的形成具有重要作用。在其中，各向异性盒的波动促进了相形成。使用一组拓扑描述符（包括协调序列和环统计）对元动力学运行进行了深入分析。结构景观历史和无定形中间体的差异对于选择性地形成特定亚稳态的多晶型物至关重要，将晶体结构预测转化为实际材料。
The response to compression of the clathrate type-II structure Ge(cF136) is investigated by means of \textit{ab initio} small-cell metadynamics at different temperatures and pressures. At lower pressure $p$=2.5 GPa the metastable metallic bct-5 phase competes against $β$-Sn Ge(tI4), which forms at higher pressures. On lowering temperature, the presence of amorphous intermediates obtained from Ge$_{136}$ is more pronounced and is instrumental to the formation of denser structural motifs, from which metallic bct-5 can form. Therein, anisotropic box fluctuations promote phase formation. The metadynamics runs are analysed in depth using a set of topological descriptors, including coordination sequence and ring statistics. Differences in the structural landscape history and amorphous intermediates are critical for the selective formation of particular metastable polymorphs, towards turning crystal structure predictions into actual materials.
