Photoinduced phenomena in correlated electron systems with multi-degrees of freedom
Photoinduced phenomena in correlated electron systems with multi-degrees of freedom
复制标题
多自由度相关电子系统中的光致现象
DOI：
10.1140/epjst/e2013-01910-4
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
and Yu Kanamori
中科院分区：
文献类型：
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作者：
Sumio Ishihara;Jun Ohara;and Yu Kanamori
研究了自旋-电荷耦合强关联电子系统的光生电子动力学。基于最近在钙钛矿锰氧化物和钴氧化物中的光泵浦探测实验，对双交换系统和自旋态跃迁系统进行了理论分析。首先，我们研究了光激发态下的双交换相互作用。自旋和电荷结构的时间演化作为泵光子振幅的函数进行检查。在弱抽运情况下，初始电荷有序的反铁磁绝缘态有转变为铁磁金属态的趋势。另一方面，在强抽运情况下，光辐照后，初始反铁磁关联和绝缘特性增强。这种意想不到的光激发态可以通过超快光学测量来检测。其次，在自旋态跃迁系统中，利用含时平均场近似对双带Hubbard模型进行了分析。通过在低自旋带绝缘体中引入光子，通过由电子带宽度控制的电子-空穴对湮灭过程产生高自旋态。我们还考虑了相对论自旋轨道相互作用，并比较了有无自旋轨道相互作用的结果。
Photo-induced electronic dynamics in strongly correlated electron system with spin-charge coupling are studied. Motivated from recent optical pump-probe experiments in perovskite manganites and cobaltites, the double-exchange system and the spin-state transition system are theoretically analyzed. First, we focus on the double-exchange interaction in photo-excited state. The time evolutions for the spin and charge structures are examined as functions of the pump photon amplitudes. In the weak-pumping case, the initial charge-ordered antiferromagnetic insulating state tends to become the ferromagnetic metallic state. On the other hand, in the strong-pumping case, the initial antiferromagnetic correlation and insulating character are enhanced after photoirradiation. This unexpected photo-excited state is detectable by the ultrafast optical measurement. Second, in the spin-state transition system, the two-band Hubbard model is analyzed by the time-dependent mean-field approximation. By introducing photons in the low-spin band insulator, high-spin states are generated through the electron-hole pair annihilation process which is governed by the electron band width. We also take into account the relativistic spin-orbit interaction, and compare the results with and without the spin-orbit interaction.