Dissipative Floquet topological systems
Dissipative Floquet topological systems
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DOI：
10.1103/physrevb.90.195429
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发表时间：
2014-11-20
影响因子：
3.7
通讯作者：
Mitra, Aditi
中科院分区：
文献类型：
--
作者：
Dehghani, Hossein;Oka, Takashi;Mitra, Aditi
受最近的泵浦探测光谱的启发，我们研究了声子耗散和势冷却对Floquet拓扑态非平衡分布函数的影响。为此，我们应用Floquet动力学方程的方法来研究二维狄拉克费米子照射的圆偏振激光，一个系统，预计将在激光诱导的量子霍尔态。我们发现，初始电子分布显示出各向异性的动量依赖的自旋纹理，其属性是由激光的开关协议控制。声子然后平滑这一点，导致一个非平凡的各向同性非平衡分布，它没有初始状态和初始开关协议的记忆，但不同于热状态。在狄拉克点的分布的解析表达式，得到相关的观察量子化运输。
Motivated by recent pump-probe spectroscopies, we study the effect of phonon dissipation and potential cooling on the nonequilibrium distribution function in a Floquet topological state. To this end, we apply a Floquet kinetic equation approach to study two-dimensional Dirac fermions irradiated by a circularly polarized laser, a system which is predicted to be in a laser-induced quantum Hall state. We find that the initial electron distribution shows an anisotropy with momentum-dependent spin textures whose properties are controlled by the switching-on protocol of the laser. The phonons then smoothen this out, leading to a nontrivial isotropic nonequilibrium distribution which has no memory of the initial state and initial switch-on protocol, and yet is distinct from a thermal state. An analytical expression for the distribution at the Dirac point is obtained that is relevant for observing quantized transport.