Auger Recombination of Photogenerated Charges in One-Dimensional Mott Insulators
Auger Recombination of Photogenerated Charges in One-Dimensional Mott Insulators
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DOI：
10.1143/jpsj.80.084721
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发表时间：
2011-08-01
影响因子：
1.7
通讯作者：
Aihara, Masaki
中科院分区：
文献类型：
--
作者：
Segawa, Mami;Takahashi, Akira;Aihara, Masaki
从理论上研究了一维莫特绝缘子的光激发态动力学。采用parier - parr - people模型，对光脉冲激发非平衡态的时间发展进行了数值计算。在较弱的光激发情况下，最大光激发密度低于18%左右，光激发态的载流子是双胶子和双胶子，结合的双胶子-双胶子对的双极复合即俄歇复合过程主导了具有现实库仑参数的光生的双胶子和双胶子的衰变。在密度大于该值的强光激发情况下，光激发态的载流子不能用空子和双元来描述。因此，双布隆-荷子对的俄歇复合过程并不是光生电荷的主要衰变途径。此外，自旋和电荷自由度是耦合的，在光激发态中发生自旋弛豫。随着光生载流子密度的增大，衰减时间减小。这种趋势与实验相一致。
We theoretically investigate the dynamics of photoexcited states in one-dimensional Mott insulators. We adopt the Pariser-Parr-Pople model, and numerically calculate the time development of the nonequilibrium state excited by a light pulse. In the weaker light excitation case where the maximum photoexcitation density is below about 18%, the charge carriers in the photoexcited states are holons and doublons, and the geminate recombination of bound doublon-holon pairs, namely, the Auger recombination process dominates the decay of the photogenerated holons and doublons with the realistic Coulomb parameters. In the stronger light excitation case where the density is above the value, the charge carriers of the photoexcited states cannot be described by holons and doublons. As a result, the Auger recombination process of doublon-holon pairs is not the main decay route of the photogenerated charges. Furthermore, the spin and the charge degrees of freedom are coupled, and spin relaxation occurs in the photoexcited states. As the density of the photogenerated charge carriers becomes larger, the decay time decreases. This tendency is consistent with experiments.