School of Science, Henan Institute of Technology, XinXiang, 453003, China.
Phys Chem Chem Phys. 2023 Jun 15;25(23):15815-15821. doi: 10.1039/d3cp01293j.
By combining a hexagon and square carbon ring, a series of two-dimensional (2D) carbon allotropes, named (HS)-graphene, can be obtained. Based on the first-principles calculations, the energetic, dynamical and mechanical stability were evaluated. Importantly, we predicted that some carbon allotropes possess the Dirac cone structure. A pair of Dirac points can be found for (HS)-graphene and (HS)-graphene in the first Brillouin zone. With varying the number of four- and six-membered rings, a distorted Dirac cone can be observed for (HS)-graphene and (HS)-graphene. To get insight into the features of the Dirac cone, the orbital decomposed band structure, the corresponding density of states, the projection map of the three-dimensional bands and Fermi velocity were investigated. Interestingly, the Fermi velocity of (HS)-graphene is up to 8.8 × 10 m s along the direction, which is higher than that of graphene, indicating higher potential application in electronic transport. Finally, we discuss the mechanical properties of (HS)-graphene. Our work provides a new way to design the stable 2D carbon allotropes with a Dirac cone.
通过将六边形和正方形碳环相结合，可以得到一系列二维（2D）碳同素异形体，命名为（HS）-石墨烯。基于第一性原理计算，评估了其能量、动力学和力学稳定性。重要的是，我们预测了一些碳同素异形体具有狄拉克锥结构。在第一布里渊区中，可以发现（HS）-石墨烯和（HS）-石墨烯具有一对狄拉克点。随着四元和六元环数量的变化，可以观察到（HS）-石墨烯和（HS）-石墨烯的扭曲狄拉克锥。为了深入了解狄拉克锥的特征，我们研究了轨道分解能带结构、相应的态密度、三维能带的投影图和费米速度。有趣的是，（HS）-石墨烯在 方向上的费米速度高达 8.8×10 m s，高于石墨烯，表明在电子输运方面有更高的潜在应用。最后，我们讨论了（HS）-石墨烯的力学性能。我们的工作为设计具有狄拉克锥的稳定二维碳同素异形体提供了一种新方法。
