Prediction of Host-Guest Na-Fe Intermetallics at High Pressures
Prediction of Host-Guest Na-Fe Intermetallics at High Pressures
复制标题
高压下主客体 Na-Fe 金属间化合物的预测
DOI：
10.1021/acs.inorgchem.6b00881
复制
发表时间：
2016
影响因子：
4.6
通讯作者：
Ma Yanming
中科院分区：
文献类型：
--
作者：
Zhou Yuanyuan;Wang Hui;Zhu Chunye;Liu Hanyu;Tse John S.;Ma Yanming
高压可以从根本上改变元素金属的电子结构，导致意外形成具有不同寻常结构特征的金属间化合物。本文采用无偏结构搜索方法，结合密度泛函理论计算，研究了Na-Fe金属间化合物在压力作用下的相稳定性和结构变化。两种具有化学计量的金属间化合物Na3Fe和Na4Fe分别在120和155 GPa以上的压力下具有热力学稳定性。一个有趣的结构特征是，两者都形成了一种主-客状结构，其Na亚晶格由大小多边形构成，类似于在第I组和第II组元素中观察到的自宿主不相称相的宿主框架。除了在大通道中运行的一维（1D）铁链外，更有趣的是，在层之间的小通道中发现了电极。电子拓扑分析表明，铁原子与间隙电子之间的二级键相互作用有助于稳定这些结构。
High pressure can fundamentally alter the electronic structure of elemental metals, leading to the unexpected formation of intermetallics with unusual structural features. In the present study, the phase stabilities and structural changes of Na–Fe intermetallics under pressure were studied using unbiased structure searching methods, combined with density functional theory calculations. Two intermetallics with stoichiometries Na3Fe and Na4Fe are found to be thermodynamically stable at pressures above 120 and 155 GPa, respectively. An interesting structural feature is that both have form a host–guest-like structure with Na sublattices constructed from small and large polygons similar to the host framework of the self-hosting incommensurate phases observed in Group I and II elements. Apart from the one-dimensional (1D) Fe chains running through the large channels, more interestingly, electrides are found to localize in the small channels between the layers. Electron topological analysis shows secondary bonding interactions between the Fe atoms and the interstitial electrides help to stabilize these structures.