论文标题
ta $ _2 $ nise $ _5 $的超快反转的超快逆转签名
Signatures of ultrafast reversal of excitonic order in Ta$_2$NiSe$_5$
论文作者
论文摘要
在存在电子 - 音波耦合的情况下，一种激子绝缘子具有由Ising型阶阶参数描述的两个变性基态。从微观汉密尔顿（Hamiltonian）开始，我们得出了声子耦合的激子绝缘子TA $ _2 $ _2 $ nise $ _5 $中的ISING订单参数方程，并证明它可以使用适当的激光脉冲序列在Ultrashort TimeScales上可控。通过理论和时间分辨的光学反射率测量的组合，我们报告了基于其相干兴奋的订单参数偶联的声子的异常行为，以ta $ _2 $ _2 $ _5 $中的这种顺序参数逆转的证据。我们的工作扩大了超级订单参数控制的领域，超出了自旋和电荷有序材料。
In the presence of electron-phonon coupling, an excitonic insulator harbors two degenerate ground states described by an Ising-type order parameter. Starting from a microscopic Hamiltonian, we derive the equations of motion for the Ising order parameter in the phonon coupled excitonic insulator Ta$_2$NiSe$_5$ and show that it can be controllably reversed on ultrashort timescales using appropriate laser pulse sequences. Using a combination of theory and time-resolved optical reflectivity measurements, we report evidence of such order parameter reversal in Ta$_2$NiSe$_5$ based on the anomalous behavior of its coherently excited order-parameter-coupled phonons. Our work expands the field of ultrafast order parameter control beyond spin and charge ordered materials.
