论文标题
从头开始研究准二进制乙腈sr $ _3 $ [c $ _2 $ n] $ _ 2 $
Ab initio study on Quasi-Binary Acetonitriletriide Sr$_3$[C$_2$N]$_2$
论文作者
论文摘要
我们使用密度功能理论（DFT）报告，这是最近合成和表征的SR $ _3 $ [C $ _2 $ n] $ _ 2 $ CRYSTAL的基础属性。几乎无色的，中心对称SR $ _3 $ [C $ _2 $ n] $ _ 2 $ _ 2 $在单斜单元中结晶，其中有$ p2_1/c $ space Group（第14号），其许多属性仍然是未知的基础，因为它是该领域的下一部分。这项研究的目的是通过理论预测来填补这一信息差距。计算出的结构属性与克拉克（Clark）和同事领导的实验组获得的结构属性相媲美，从而使我们对SR $ _3 $ [C $ _2 $ n] $ _ 2 $的DFT计算的准确性具有更大的信心。我们采用了相同的方法来计算机械和动力学稳定性，以及sr $ _3 $ [c $ _2 $ n] $ _ 2 $的电子密度。没有观察到虚构的声子模式，因此暗示了动态稳定性。计算出的13个弹性常数通过了单斜系统的稳定性标准。从计算的泊松比（$η$ = 0.27）和g/b = 0.54，我们的计算预测SR $ _3 $ [C $ _2 $ n] $ _ 2 $被脆弱并且无法承受高压应用程序。为了分析化学键合机制，绘制了相应的状态总密度（TDOS）和部分DOS。价带（VB）的顶部主要由C 2P状态n 2p，n 2s和SR 5S状态的轻微混合。传统带（CB）的底部显示C 2P，N 2P，N 2S和SR 5S状态之间的杂交，在整个传导带中产生7.18 eV的带宽。我们能够在SR $ _3 $ [C $ _2 $ N] $ _ 2 $中获得2.65 ev的可调电子间隙。这里的作者指出，Sr $ _3 $ [C $ _2 $ n] $ _ 2 $落在一个未知的伪硝酸家族中，可能具有新颖的物理和化学特性。
We report using density functional theory (DFT), the ground-state properties of the recently synthesized and characterized Sr$_3$[C$_2$N]$_2$ crystal. The nearly colorless, centrosymmetric Sr$_3$[C$_2$N]$_2$ crystallizes in a monoclinic unit cell with a $P2_1/c$ space group (No.14) and many of its properties remain unknown basing on the fact that it's a latecomer in the field. The goal of this study is to fill this information gap through a theoretical prediction. The calculated structural properties were comparable to those obtained by an experimental group led by Clark and co-workers thus giving us extra confidence in the accuracy of our DFT computations on Sr$_3$[C$_2$N]$_2$. We employed the same approach in calculating mechanical and dynamical stabilities together with the electronic density of states of Sr$_3$[C$_2$N]$_2$. No imaginary phonon modes were observed and thus implying dynamical stability. The thirteen elastic constants calculated passed the stability criteria of a monoclinic system. From the computed Poisson's ratio ($η$=0.27) and G/B=0.54, our calculations predict Sr$_3$[C$_2$N]$_2$ being brittle and not able to withstand high-pressure applications. To analyze the chemical bonding mechanism, the corresponding total density of states (TDOS) and partial DOS were plotted. The top of the valence band (VB) mainly consists of C 2p states N 2p, N 2s and a slight admixture of Sr 5s states. The bottom of the conduction band (CB) shows a strong hybridization between C 2p, N 2p, N 2s, and Sr 5s states, yielding a bandwidth of 7.18 eV in the entire conduction band. We were able to obtain a tunable electronic gap of 2.65 eV in Sr$_3$[C$_2$N]$_2$. The authors herein note that Sr$_3$[C$_2$N]$_2$ falls in an unknown family of pseudonitrides that may possess novel physical and chemical properties.
