论文标题
在30 $^{\ circ} $扭曲的双层石墨烯中，ic晶电子状态的压力和电场依赖性
Pressure and electric field dependence of quasicrystalline electronic states in 30$^{\circ}$ twisted bilayer graphene
论文作者
论文摘要
30 $^{\ circ} $扭曲的双层石墨烯以12倍对称性演示了Quasicrystalline电子状态。但是，这些状态远离费米水平，这使得传统的迪拉克·费米（Dirac Fermion）行为主导了该系统中低能谱。通过使用紧密结合近似，我们研究了外部压力和电场对准晶体电子状态的影响。我们的结果表明，通过施加垂直于石墨烯平面的压力，可以将准晶电子状态推向费米水平。然后，$ \ sim $ $ 4 \ times10^{14} $ $ $ cm^{ - 2} $的订单的电子或孔掺杂足以使费米级与这些Quasicrystalline状态的巧合。此外，我们的研究表明，应用垂直于石墨烯平面的电场可以破坏这些状态的12倍对称性并破坏12波状态的能量退化，并且在传导带中与价带相比，在传导带中更容易。重要的是，压力的施加可以在一定程度上恢复这些状态的12倍对称性。我们提出了一个杂交图片，可以解释所有这些现象。
30$^{\circ}$ twisted bilayer graphene demonstrates the quasicrystalline electronic states with 12-fold symmetry. These states are however far away from the Fermi level, which makes conventional Dirac fermion behavior dominating the low energy spectrum in this system. By using tight-binding approximation, we study the effect of external pressure and electric field on the quasicrystalline electronic states. Our results show that by applying the pressure perpendicular to graphene plane one can push the quasicrystalline electronic states towards the Fermi level. Then, the electron or hole doping of the order of $\sim$ $4\times10^{14}$ $cm^{-2}$ is sufficient for the coincidence of the Fermi level with these quasicrystalline states. Moreover, our study indicates that applying the electric field perpendicular to the graphene plane can destroy the 12-fold symmetry of these states and break the energy degeneracy of the 12-wave states, and it is easier to reach this in the conduction band than in the valence band. Importantly, the application of the pressure can recover the 12-fold symmetry of these states to some extent against the electric field. We propose a hybridization picture which can explain all these phenomena.
