First-principles calculations on solid nitrogen: A comparative study of high-pressure phases
First-principles calculations on solid nitrogen: A comparative study of high-pressure phases
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DOI：
10.1103/physrevb.77.144109
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发表时间：
2008-04-01
影响因子：
3.7
通讯作者：
Albe, K.
中科院分区：
文献类型：
--
作者：
Kotakoski, J.;Albe, K.
有实验证据表明，氮在压力下形成聚合固体。在这项研究中，我们比较了各种固体氮相通过从头计算的基础上密度泛函理论来描述固体氮在不同的压力。我们表明，在所有三个维度的共价键的两个阶段是积极的最有利的压力为50-200 GPa和层状黑磷相的焓变得较低，在压力超过200 GPa，至少在低温下。然而，根据我们的研究结果，黑磷在接近200 GPa的压力下是不稳定的。我们进一步提出了在几个压力下的相关已知相的能带结构和态密度计算，并表明黑磷是金属亚稳态时，而较低的压力相保持介电与压力相关的带隙。还提出了一些以前提出的结构的可疑的实验相关性。
There is experimental evidence that nitrogen forms a polymeric solid under pressure. In this study, we compare various solid nitrogen phases by means of ab initio calculations based on density-functional theory to describe solid nitrogen at different pressures. We show that two phases with covalent bonds in all three dimensions are energetically the most favored at pressures of 50-200 GPa and that the layered black phosphorus phase becomes lower in enthalpy at pressures exceeding 200 GPa, at least at low temperatures. However, according to our results, black phosphorus is unstable at pressures close to 200 GPa. We further present band structure and density of states calculations for the relevant known phases at several pressures and show that black phosphorus is metallic when metastable, whereas the lower-pressure phases remain dielectric with pressure-dependent band gaps. Also the questionable experimental relevance of several of the previously proposed structures is addressed.