通过遗传算法探索高压下的BaCN₂物相
High-pressure BaCN$_2$ phases explored by genetic algorithm
AI总结：
本研究采用结合从头算电子结构计算的遗传算法搜索BaCN₂的高压晶体结构，复现了低压相并预测42GPa以上会出现含CN₃平面三角单元线性网络的Ima2聚合相，为金属碳二亚胺高压物相及高能量密度材料研究提供参考。
摘要：
含氮聚合物因在高能量密度材料（HEDMs）中的应用受到广泛关注，这类材料的能量蕴含于三键中。近年来已有金属碳二亚胺MCN₂的合成报道，但此类聚合相是否会出现在其高压物相中仍是一个值得研究的问题，目前针对其高压晶体结构的研究较少。我们采用结合了从头算电子结构计算的遗传算法开展结构搜索，以探究BaCN₂高压相中可能存在的晶体结构。该结构搜索成功复现了此前报道的较低压力范围内的晶体结构。在验证了预测能力的可靠性后，遗传搜索进一步预测出一种具有Ima2空间群的聚合相，会在42 GPa以上的更高压力下出现。该聚合相具有由CN₃平面三角单元构成的线性网络结构。可以认为，高压下相互靠近的阴离子位点单元CN₂彼此直接形成共价键，从而稳定了该物相。
英文摘要：
Polymers containing nitrogen have attracted much attention in connection with their application to high energy density materials (HEDMs), in which energy is inherent in the triple bond. It is an interesting question whether such polymerized phases appear in the high-pressure phase of metal carbodiimide MCN$_2$, of which synthesis have been reported in recent years, but few studies have investigated the crystal structure at high pressure. We have adopted a structure search based on the genetic algorithm coupled with ab initio electronic structure calculations to investigate possible crystal structures that may appear in the high-pressure phase of BaCN$_2$. The structure search successfully reproduced the previously reported crystal structures in the lower pressure range. With confirmed reliability of its predictive ability, the genetic search further predicts a polymerized phase with Ima2 appearing at higher pressure above 42 GPa. The polymerized phase takes the structure of a linear network of CN$_3$ planar triangular units. It is understood that the anion site units CN$_2$, which are close to each other under high pressure, form covalent bonds directly with each other and stabilize the phase.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
