Ultrafast Quenching of the Exchange Interaction in a Mott Insulator
Ultrafast Quenching of the Exchange Interaction in a Mott Insulator
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DOI：
10.1103/physrevlett.113.057201
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发表时间：
2014-07-29
影响因子：
8.6
通讯作者：
Eckstein, M.
中科院分区：
文献类型：
--
作者：
Mentink, J. H.;Eckstein, M.
我们研究了光载流子激发如何快速和有效地改变Mott-Hubbard原型绝缘体中的交换相互作用J（ex）。我们证明了J（ex）的超快猝灭，既通过从时间依赖的响应形式中评估交换积分，也通过明确地模拟由外部磁场倾斜的反铁磁体中激光诱导的自旋进动。在这两种情况下，电子动力学都是由非平衡动力学平均场理论得到的。我们发现，经过修饰的J（ex）在脉冲后的几次电子跳跃时间内就已经出现，其还原效果与化学掺杂的效果相当。
We investigate how fast and how effective photocarrier excitation can modify the exchange interaction J(ex) in the prototype Mott-Hubbard insulator. We demonstrate an ultrafast quenching of J(ex) both by evaluating exchange integrals from a time-dependent response formalism and by explicitly simulating laser-induced spin precession in an antiferromagnet that is canted by an external magnetic field. In both cases, the electron dynamics is obtained from nonequilibrium dynamical mean-field theory. We find that the modified J(ex) emerges already within a few electron hopping times after the pulse, with a reduction that is comparable to the effect of chemical doping.