Brillouin-Wigner theory for Floquet topological phase transitions in spin-orbit-coupled materials
Brillouin-Wigner theory for Floquet topological phase transitions in spin-orbit-coupled materials
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自旋轨道耦合材料中 Floquet 拓扑相变的布里渊-维格纳理论
DOI：
10.1103/physrevb.94.235419
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发表时间：
2016
影响因子：
3.7
通讯作者：
Sumathi Rao
中科院分区：
文献类型：
--
作者：
Priyanka Mohan;Ruchi Saxena;A. Kundu;Sumathi Rao
基于Brillouin-Wigner （B-W）微扰理论，建立了具有自旋-轨道耦合驱动系统的高频展开，适用于硅烯、锗烯和斯坦烯的情况。我们计算了零光子子空间中的有效哈密顿量，不仅阶为$O(\omega^{-1})$，而且将所有重要项都保持阶为$O(\omega^{-2})$，并获得了跳变项和自旋轨道项的光辅助校正项，以及新的更长距离跳变项。然后，我们利用有效静态哈密顿量计算了高频极限下的相图，并将其与Floquet带陈恩数的直接数值计算结果进行了比较，结果表明，在足够大的频率下，B-W理论高频展开即使在自旋轨道耦合项存在的情况下也能很好地工作。
We develop the high frequency expansion based on the Brillouin-Wigner (B-W) perturbation theory for driven systems with spin-orbit coupling which is applicable to the cases of silicene, germanene and stanene. We compute the effective Hamiltonian in the zero photon subspace not only to order $O(\omega^{-1})$, but by keeping all the important terms to order $O(\omega^{-2})$, and obtain the photo-assisted correction terms to both the hopping and the spin-orbit terms, as well as new longer ranged hopping terms. We then use the effective static Hamiltonian to compute the phase diagram in the high frequency limit and compare it with the results of direct numerical computation of the Chern numbers of the Floquet bands, and show that at sufficiently large frequencies, the B-W theory high frequency expansion works well even in the presence of spin-orbit coupling terms.