论文标题
有效的Floquet Hamiltonians，用于定期驱动的双层石墨烯
Effective Floquet Hamiltonians for periodically-driven twisted bilayer graphene
论文作者
论文摘要
我们为扭曲的双层石墨烯提供了有效的浮球哈密顿量，该石墨烯是由圆形极化光驱动的两个不同驱动器，高频制度的不同机制。首先，我们考虑一种与频率小于带宽和弱幅度的实验相关的驱动方案，并得出有效的哈密顿量，该实验通过对称分析提供了对驱动器丰富效应的分析见解。我们发现，低频下的圆形光线可以选择性地降低AA型中层跳跃的强度，而使AB型不受影响。然后，我们考虑中间频率和中等强度驱动方案。我们提供了一种紧凑而准确的有效哈密顿量，我们与Van Vleck的扩张进行了比较，并证明它提供了确切的准耐药的明显改进的表示。最后，我们讨论了驱动器对对称性，费米速度和Floquet扁平带的差距的影响。
We derive effective Floquet Hamiltonians for twisted bilayer graphene driven by circularly polarized light in two different regimes beyond the weak-drive, high frequency regime. First, we consider a driving protocol relevant for experiments with frequencies smaller than the bandwidth and weak amplitudes and derive an effective Hamiltonian, which through a symmetry analysis, provides analytical insight into the rich effects of the drive. We find that circularly polarized light at low frequencies can selectively decrease the strength of AA-type interlayer hopping while leaving the AB-type unaffected. Then, we consider the intermediate frequency, and intermediate-strength drive regime. We provide a compact and accurate effective Hamiltonian which we compare with the Van Vleck expansion and demonstrate that it provides a significantly improved representation of the exact quasienergies. Finally, we discuss the effect of the drive on the symmetries, Fermi velocity and the gap of the Floquet flat bands.
