论文标题
发现光引起的亚赛稳态异常，由单周期Terahertz脉冲控制
Discovery of Light-induced Metastable Martensitic Anomaly Controlled by Single-Cycle Terahertz Pulses
论文作者
论文摘要
我们报告了超长光诱导的相变，其长期寿命长的马氏体异常，该异常是由阈值以上的单周期Terahertz（THz）脉冲驱动的NB $ _3 $ sn。低频电导率的非热，THZ诱导的耗竭表明，高能$γ_{12} $频段的差距增加增加，从而增强了马氏体阶段。相反，光学泵送导致$γ_{12} $差距熔化。这种光引起的非平衡性马氏体不稳定性持续到临界温度$ \ sim $ \ sim $ 100 k，即是平衡温度的两倍以上，并且可以稳定在技术上相关的纳米秒时尺度之外。与第一原则模拟一起，我们通过E $ _U $ phonons确定了结构波动的引人注目的THZ调整，以在高温下实现非均衡顺序，远远超过了平衡状态的非平衡订单。
We report on an ultrafast photoinduced phase transition with a strikingly long-lived Martensitic anomaly driven by above-threshold single-cycle terahertz (THz) pulses in Nb$_3$Sn. A non-thermal, THz-induced depletion of low frequency conductivity indicates increased gap splitting of high energy $Γ_{12}$ bands by removal of their degeneracies which enhances the Martensitic phase. In contrast, optical pumping leads to a $Γ_{12}$ gap melting. Such light-induced non-equilibrium Martensitic instability persists up to a critical temperature $\sim$100 K, i.e., more than twice the equilibrium temperature, and can be stabilized beyond technologically-relevant, nanosecond timescales. Together with first-principle simulations, we identify a compelling THz tuning of structural fluctuations via E$_u$ phonons to achieve a non-equilibrium ordering at high temperatures far exceeding those for equilibrium states.
