High-Harmonic Generation Approaching the Quantum Critical Point of Strongly Correlated Systems.
High-Harmonic Generation Approaching the Quantum Critical Point of Strongly Correlated Systems.
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DOI：
10.1103/physrevlett.128.047401
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发表时间：
2021-07
影响因子：
8.6
通讯作者：
Can Shao;Hantao Lu;Xiao Zhang;Chao Yu;T. Tohyama;R. Lu
中科院分区：
文献类型：
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作者：
Can Shao;Hantao Lu;Xiao Zhang;Chao Yu;T. Tohyama;R. Lu
利用精确对角化方法研究了强激光作用下关联系统的高次谐波产生。对于周期链上的扩展Hubbard模型，与两个相邻的带隙相（即，电荷密度波和自旋密度波状态），特别是在低频中。我们证实，在QCP附近的系统是超敏感的外场和更多的光跃迁通道通过激发态是负责高次谐波。这一特点具有通过使用接近QCP的材料获得高效率谐波的潜力。基于二维Halfton模型，我们进一步提出，产生的谐波的偶或奇阶分量可以被视为频谱信号，以区分拓扑有序的相位从局部有序的。我们的发现为在强关联材料中实现超快光源和在强激光场中用非线性光学研究量子相变铺平了道路。
By employing the exact diagonalization method, we investigate the high-harmonic generation (HHG) of the correlated systems under the strong laser irradiation. For the extended Hubbard model on a periodic chain, HHG close to the quantum critical point (QCP) is more significant compared to two neighboring gapped phases (i.e., charge-density-wave and spin-density wave states), especially in low frequencies. We confirm that the systems in the vicinity of the QCP are supersensitive to the external field and more optical-transition channels via excited states are responsible for HHG. This feature holds the potential of obtaining high-efficiency harmonics by making use of materials approaching QCP. Based on the two-dimensional Haldane model, we further propose that the even- or odd-order components of generated harmonics can be promisingly regarded as spectral signals to distinguish the topologically ordered phases from locally ordered ones. Our findings in this Letter pave the way to achieve ultrafast light source from HHG in strongly correlated materials and to study quantum phase transition by nonlinear optics in strong laser fields.