Nonequilibrium susceptibility in photoinduced Floquet states
Nonequilibrium susceptibility in photoinduced Floquet states
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DOI：
10.1103/physrevb.100.075127
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发表时间：
2018-11
影响因子：
3.7
通讯作者：
A. Ono;S. Ishihara
中科院分区：
文献类型：
--
作者：
A. Ono;S. Ishihara
研究了光致Floquit态的非平衡磁化率。我们分析了在时间周期振荡电场中与热浴耦合的电子系统。自旋/电荷磁化率是在Floquet格林函数方法的基础上推导出来的，并在较宽的光幅和频率范围内进行了数值计算。当频率大于带宽时，由于动力学局域化效应，磁化率增大，并且它们在动量空间中的峰位因费米面形变而移动。在频率和幅度较小的情况下，磁化率出现多峰结构，起源于跨越费米能级的多个Floquite带。为了证实这些数值结果并给出解释，我们推导出了小电场幅值时磁化率的近似表达式。
Nonequilibrium susceptibility in photoinduced Floquet states is studied. We analyze an electron system coupled with a heat bath in a time-periodic oscillating electric field. Spin/charge susceptibility is formulated on the basis of the Floquet Green function method, and is calculated numerically in a wide range of amplitude and frequency of light. When the frequency is larger than the bandwidth, the susceptibility is enhanced due to the dynamical localization effect, and their peak positions in the momentum space are shifted by the Fermi surface deformation. In the case of the small frequency and amplitude, multiple-peak structure emerges in the susceptibility, originating from the multiple Floquet bands which cross the Fermi level. To confirm those numerical results and provide the interpretation, an approximated expression of the susceptibility is derived for small electric-field amplitude.