Phonon-dressed states in an organic Mott insulator
Phonon-dressed states in an organic Mott insulator
复制标题
有机莫特绝缘体中的声子修饰态
DOI：
10.1038/s42005-022-00838-x
复制
发表时间：
2022
影响因子：
5.5
通讯作者：
T. Miyamoto and H. Okamoto
中科院分区：
文献类型：
--
作者：
N. Sono;T. Otaki;T. Kitao;T.Yamakawa;D. Sakai;T. Morimoto;T. Miyamoto and H. Okamoto
在由飞秒激光脉冲激发的固体电子系统中，通过原始电子波函数和光的周期性电场的耦合创建了称为光子修饰态的新量子态。光子修饰态的研究是非线性光学科学的一个中心问题，因为与光子修饰态相关的相干响应可以引起超快光开关现象。然而，一般来说，光子修饰态的相敏动力学由于其寿命短而难以观察。在这里，我们表明，用强中红外脉冲激发有机莫特绝缘体四氰基对醌二甲烷钾会引起几次分子内振动，从而为电子系统增加时间周期性电势，从而在皮秒时域中产生声子修饰态。通过使用相位稳定的中红外脉冲作为激发和超短可见脉冲作为探针的子周期光谱，我们观察到由两种分子内振动的双频、和频和差频的四种相干振荡组成的光辐射。每个振荡的探针能量依赖性可以用 Floquet 理论框架中的声子修饰态很好地解释。这些发现为具有强电荷-声子耦合的相关电子材料的 Floquet 工程提供了可能性。
In an electronic system of solids excited by a femtosecond laser pulse, new quantum states called photon-dressed states are created via the coupling of original electron wavefunctions and periodic electric fields of light. The study of photon-dressed states is a central issue in nonlinear optical science, as a coherent response associated with a photon-dressed state can cause ultrafast optical-switching phenomena. In general, however, phase-sensitive dynamics of photon-dressed states are difficult to observe due to their short lifetime. Here, we show that excitation of the organic Mott insulator potassium-tetracyanoquinodimethane with a strong mid-infrared pulse induces a couple of intramolecular vibrations, which add temporally periodic potentials to the electronic system, giving rise to phonon-dressed states in the picosecond time domain. Through sub-cycle spectroscopy using a phase-stable mid-infrared pulse as an excitation and an ultrashort visible pulse as a probe, we observe optical radiation consisting of four kinds of coherent oscillations with double, sum, and differential frequencies of two intramolecular vibrations. The probe-energy dependence of each oscillation can be well interpreted with phonon-dressed states in the framework of Floquet theory. These findings open a possibility for Floquet engineering in correlated electron materials with strong charge–phonon couplings.