论文标题
三价灯笼二硝酸盐的高压计算搜索
High pressure computational search of trivalent lanthanide di-nitrides
论文作者
论文摘要
过渡金属氮化物吸引了科学界对其吸引人的特性和技术应用的极大兴趣。在这里，我们专注于Dinitride（Yn $ _ {2} $）及其在压力下的形成和结构过渡。我们采用了固定的构图USPEX搜索来找到最稳定的多晶型物。我们选择YTTrium作为灯笼系列的代理，因为它的氧化状态仅为$+3 $，这与大多数过渡金属相反。然后，我们计算了这些结构的热力学和动力学稳定性与分解反应相比，我们发现化合物经历了两个结构过渡，后者显示了地层n $ _ {4} $链。仔细观察氮键的性质表明，在前两个结构中，氮形成二聚体，键长在单个键和双键的键之间中间，因此很难使Yn $ _ {2} $的适当氧化状态构型合理化。在后一种结构中，有n $ _ {4} $链的形成，债券长度显着增加，最高为可以证明是单个债券合理的值。最后，我们还研究了我们发现的结构的电子结构和动力稳定性。
Transition metal nitrides have attracted much interest of the scientific community for their intriguing properties and technological applications. Here we focus on yttrium dinitride (YN$_{2}$) and its formation and structural transition under pressure. We employed a fixed composition USPEX search to find the most stable polymorphs. We choose yttrium as a proxy for the lanthanide series because it has only $+3$ oxidation state, contrary to most transition metals. We then computed thermodynamic and dynamical stability of these structures compared to the decomposition reactions and we found that the compound undergoes two structural transitions, the latter showing the formation N$_{4}$ chains. A closer look into the nature of the nitrogen bonding showed that in the first two structures, where nitrogen forms dimers, the bond length is intermediate between that of a single bond and that of a double bond, making it hard to rationalize the proper oxidation state configuration for YN$_{2}$. In the latter structure where there is the formation of N$_{4}$ chains, the bond lengths increase significantly, up to a value that can be justified as a single bond. Finally, we also studied the electronic structure and the dynamical stability of the structures we found.
