标题： 相干铁磁振子的观测 显示英文标题

标题： Observation of Coherent Ferrons

摘要： 有序相的激发会产生准粒子和集体模式，如磁有序产生的磁振子所证明的那样，磁振子在信息传输和量子互连中有应用。 将这一范式扩展到铁电材料表明存在铁子，即铁电有序集体激发的基本量子单元，这是鲍尔及其同事理论发展起来的。 虽然相干磁振子在广泛的实验中被观察到，但相干铁子却逃避了实验检测。 鉴于电偶极子相互作用（铁电）本质上比它们的磁性对应物更强，这种差异尤为引人注目。 在这里，我们报告了在范德华（vdW）铁电材料NbOI2中生成和传输相干铁子。 通过使用短激光脉冲激发铁电偶极子的集体振荡，我们从强烈的窄带太赫兹（THz）发射中识别出相干铁子，并观察到它们沿着极化方向以超过10^5 m/s的超声速速度传播。 太赫兹发射是一种二阶非线性过程，需要铁电有序，这一点在结构相关的铁电材料WO2Br2和非铁电材料TaOBr2中得到证实。 相干铁子的发现为许多应用铺平了道路，包括窄带太赫兹发射、铁子信息处理和量子互连。 显示英文摘要

摘要： Excitation of ordered phases produces quasiparticles and collective modes, as exemplified by magnons that emerge from magnetic order, with applications in information transmission and quantum interconnects. Extending this paradigm to ferroelectric materials suggests the existence of ferrons, i.e. fundamental quanta of the collective excitation of ferroelectric order5 developed theoretically by Bauer and coworkers. While coherent magnons are observed in a broad range of experiments, coherent ferrons have eluded experimental detection. This discrepancy is particularly intriguing given that electric dipole interactions (FE) are inherently stronger than their magnetic counterparts. Here, we report the generation and transport of coherent ferrons in the van der Waals (vdW) ferroelectric material NbOI2. By launching collective oscillations of the ferroelectric dipoles using a short laser pulse, we identify coherent ferrons from intense and narrow-band terahertz (THz) emission and observe their propagations along the polar direction at extremely hypersonic velocities exceeding 10^5 m/s. The THz emission is a second-order nonlinear process that requires ferroelectric order, as is confirmed in the structurally related ferroelectric WO2Br2 and non-ferroelectric TaOBr2. The discovery of coherent ferrons paves the way for numerous applications, including narrow-band THz emission, ferronic information processing, and quantum interconnects.