论文标题
有效的Chebyshev多项式方法计算量子电导：应用于扭曲的双层石墨烯
Efficient Chebyshev polynomial approach to quantum conductance calculations: Application to twisted bilayer graphene
论文作者
论文摘要
近年来，紧密结合绿色功能的Chebyshev多项式扩展已成功地用于研究材料的各种光谱和运输特性。但是，由于缺乏适当的Chebyshev扩展Landaeur公式的扩展或在Keldysh的攻击性理论中Green的功能而言，Chebyshev方法的应用在研究中的量子传输性能研究的研究受到了阻碍。在这里，我们通过一种混合方法来解决此问题，该方法将Chebyshev扩展的效率与复杂吸收潜力的方便相结合，以计算计算方便且准确的方式计算两端设备的电导率。该方法的多功能性用于介观扭曲的双层石墨烯（TBG）设备，最高$ 2.3 \ times10^6 $原子网站。我们的结果强调了Moiré效果，层间散射事件和扭角障碍在确定TBG魔术角$θ_m\ your Circ $ 1.1^\ Circ $的设备中的电导曲线中的重要性。
In recent years, Chebyshev polynomial expansions of tight-binding Green's functions have been successfully applied to the study of a wide range of spectral and transport properties of materials. However, the application of the Chebyshev approach to the study of quantum transport properties of noninteracting mesoscopic systems with leads has been hampered by the lack of a suitable Chebyshev expansion of Landaeur's formula or one of its equivalent formulations in terms of Green's functions in Keldysh's perturbation theory. Here, we tackle this issue by means of a hybrid approach that combines the efficiency of Chebyshev expansions with the convenience of complex absorbing potentials to calculate the conductance of two-terminal devices in a computationally expedient and accurate fashion. The versatility of the approach is demonstrated for mesoscopic twisted bilayer graphene (TBG) devices with up to $2.3\times10^6$ atomic sites. Our results highlight the importance of moiré effects, interlayer scattering events and twist-angle disorder in determining the conductance curves in devices with a small twist angle near the TBG magic angle $θ_m \approx 1.1^\circ$.
