论文标题
具有内在的III型狄拉克孔的低能石材石墨烯的理论预测
Theoretical prediction of a low-energy Stone-Wales graphene with intrinsic type-III Dirac-cone
论文作者
论文摘要
基于第一原理方法，我们预测了一种新的低能石墨烯SW40，该石墨烯SW40具有正交晶格，带有PBAM对称性和40个碳原子，形成晶体细胞，形成良好的石材 - 石 - 谷模式。 SW40计算出的总能量仅比石墨烯高约133 meV，表明其出色的稳定性超过了所有先前提出的石墨烯同种异体。我们发现，SW40的固有类型III Dirac-cone（物理学修订版，120，237403，2018）是由局部线性带和局部平面带的束缚形成的，这可能会导致系统中高度各向异性的Fermions。有趣的是，这种固有的III型狄拉克酮可以通过内层菌株有效调节，并将分别转移到II型和I型I Dirac-cones中，分别在拉伸和压缩菌株下。最后，构建了一个一般的紧密结合模型，以了解SW40中Fermi-Level附近的电子特性。结果表明，III型dirac-cone特征可以通过相邻石 - 孔缺陷之间的$π$ - 电子相互作用来很好地理解。
Based on first-principles method we predict a new low-energy Stone-Wales graphene SW40, which has an orthorhombic lattice with Pbam symmetry and 40 carbon atoms in its crystalline cell forming well-arranged Stone-Wales patterns. The calculated total energy of SW40 is just about 133 meV higher than that of graphene, indicating its excellent stability exceeds all the previously proposed graphene allotropes. We find that SW40 processes intrinsic Type-III Dirac-cone (Phys. Rev. Lett., 120, 237403, 2018) formed by band-crossing of a local linear-band and a local flat-band, which can result in highly anisotropic Fermions in the system. Interestingly, such intrinsic type-III Dirac-cone can be effectively tuned by inner-layer strains and it will be transferred into Type-II and Type-I Dirac-cones under tensile and compressed strains, respectively. Finally, a general tight-binding model was constructed to understand the electronic properties nearby the Fermi-level in SW40. The results show that type-III Dirac-cone feature can be well understood by the $π$-electron interactions between adjacent Stone-Wales defects.
