Materials Research Centre, Indian Institute of Science, Bangalore 560012, India.
Phys Chem Chem Phys. 2014 Jan 28;16(4):1667-71. doi: 10.1039/c3cp54655a.
Silicene, a graphene analogue of silicon, has been generating immense interest due to its potential for applications in miniaturized devices. Unlike planar graphene, silicene prefers a buckled structure. Here we explore the possibility of stabilizing the planar form of silicene by Ni doping using first principles density functional theory based calculations. It is found that planar as well as buckled structure is stable for Ni-doped silicene, but the buckled sheet has slightly lower total energy. The planar silicene sheet has unstable phonon modes. A comparative study of the mechanical properties reveals that the in-plane stiffness of both the pristine and the doped planar silicene is higher compared to that of the buckled silicene. This suggests that planar silicene is mechanically more robust. Electronic structure calculations of the planar and buckled Ni-doped silicene show that the energy bands at the Dirac point transform from linear behavior to parabolic dispersion. Furthermore, we extend our study to Ge and Sn sheets that are also stable and the trends of comparable mechanical stability of the planar and buckled phases remain the same.
硅烯是硅的类石墨烯材料，由于其在小型化器件中的应用潜力，引起了极大的关注。与平面石墨烯不同，硅烯倾向于形成褶皱结构。在这里，我们通过基于第一性原理密度泛函理论的计算，研究了用 Ni 掺杂来稳定硅烯平面形式的可能性。结果发现，Ni 掺杂后的硅烯无论是平面结构还是褶皱结构都是稳定的，但褶皱片的总能量略低。平面硅烯片存在不稳定的声子模式。对力学性能的比较研究表明，与褶皱硅烯相比，原始和掺杂的平面硅烯的面内弹性模量更高。这表明平面硅烯在力学上更坚固。对平面和褶皱 Ni 掺杂硅烯的电子结构计算表明，在狄拉克点处的能带从线性行为转变为抛物线色散。此外，我们将研究扩展到了 Ge 和 Sn 片，它们也是稳定的，并且平面和褶皱相的力学稳定性趋势是相同的。
