Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
J Chem Phys. 2013 Jan 14;138(2):024702. doi: 10.1063/1.4773584.
The structural and electronic properties of hydrogenated K(4) carbon as a new cubic gauche structure in I2(1)3 symmetry are investigated using first-principles calculations. The total energy for this carbon hydride (labeled by K(4)-CH) is 0.47 eV per CH unit lower than that of solid molecular cubane, suggesting its energetic stability. Based on the calculated phonon dispersion curves and electronic band structure obtained by hybrid density functional method, we find that K(4)-CH is dynamically stable and exhibits as an insulator with an indirect band gap of 6.07 eV, which is close to 6.10 eV of cubic gauche nitrogen (cg-N). To study the doping effect of nitrogen, we have also investigated N-doped K(4)-CH with a composition of C(4)H(4)N(4) in P2(1)3 symmetry. The phonon and electronic band structures show that it is dynamically stable and behaves as an insulator with an indirect band gap of 5.39 eV, smaller than that of both K(4)-CH and cg-N. These results broaden our understanding of the cubic gauche structure.
使用第一性原理计算研究了具有 I2(1)3 对称性的新型立方 gauche 结构的氢化 K(4) 碳的结构和电子性质。这种碳氢化物（标记为 K(4)-CH）的总能量比固体分子笼低 0.47eV/CH 单元，表明其能量稳定性。基于通过混合密度泛函方法获得的计算声子色散曲线和电子能带结构，我们发现 K(4)-CH 是动力学稳定的，表现为间接带隙为 6.07eV 的绝缘体，这与立方 gauche 氮（cg-N）的 6.10eV 接近。为了研究氮的掺杂效应，我们还研究了具有 P2(1)3 对称性的组成比为 C(4)H(4)N(4)的 N 掺杂 K(4)-CH。声子和电子能带结构表明它是动力学稳定的，表现为间接带隙为 5.39eV 的绝缘体，小于 K(4)-CH 和 cg-N。这些结果拓宽了我们对立方 gauche 结构的理解。
