Coherent Structural Dynamics of a Prototypical Charge-Density-Wave-to-Metal Transition
Coherent Structural Dynamics of a Prototypical Charge-Density-Wave-to-Metal Transition
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DOI：
10.1103/physrevlett.113.026401
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发表时间：
2014-07-11
影响因子：
8.6
通讯作者：
Johnson, S. L.
中科院分区：
文献类型：
--
作者：
Huber, T.;Mariager, S. O.;Johnson, S. L.
使用飞秒时间分辨的X射线衍射，我们直接监测相干晶格动力学通过超快的电荷密度波到金属过渡的原型Peierls系统K0.3MoO3在广泛的相关激发通量。而在低注量制度，我们直接遵循与集体振幅模式的结构动力学;以上的电子密度调制的熔化阈值的注量，我们观察到的周期性晶格畸变的瞬态恢复。我们可以将这些结构动力学描述为光激发后电子有序的迅速崩溃所触发的Peierls畸变的坐标沿着的运动。结果表明，结构破缺相变的动力学是由不同于初始低温态的高对称性激发态势能面决定的。
Using femtosecond time-resolved x-ray diffraction, we directly monitor the coherent lattice dynamics through an ultrafast charge-density-wave-to-metal transition in the prototypical Peierls system K0.3MoO3 over a wide range of relevant excitation fluences. While in the low fluence regime we directly follow the structural dynamics associated with the collective amplitude mode; for fluences above the melting threshold of the electronic density modulation we observe a transient recovery of the periodic lattice distortion. We can describe these structural dynamics as a motion along the coordinate of the Peierls distortion triggered by the prompt collapse of electronic order after photoexcitation. The results indicate that the dynamics of a structural symmetry-breaking transition are determined by a high-symmetry excited state potential energy surface distinct from that of the initial low-temperature state.