太赫兹诱导抗磁性量子顺电体KTaO$_3$中的声磁效应
THz-induced phonomagnetism in diamagnetic quantum paraelectric KTaO$_3$
AI总结：
本研究通过太赫兹泵浦-光学探测技术，利用圆偏振太赫兹脉冲共振激发KTaO$_3$的软极性声子，实现抗磁体中类磁响应的诱导，揭示其温度依赖特性并建立理论模型。
AI中文摘要：
当前开发新型数据操控方式的研究致力于实现磁性材料中磁化的超快控制，以及在抗磁材料中诱导磁矩。我们证明，在抗磁性量子顺电体KTaO$_3$中，振幅约为300kV/cm的圆偏振太赫兹脉冲的电场，通过共振激发其简并软极性声子，诱导出瞬态类磁响应。这种声子介导的响应通过太赫兹泵浦-光学探测技术，结合时间分辨磁光法拉第效应进行测量。我们的探测方案设置为抵消通常对瞬态响应有显著贡献的电光克尔效应的主要部分，通过减去与反向圆偏振太赫兹辐射相关的实验数据，进一步抑制了克尔效应相关信号。因此，我们能够明确识别出KTaO$_3$晶体的温度依赖类磁行为，该行为由提取的法拉第旋转体现。我们开发了一个理论模型，可定量描述测得的瞬态法拉第效应信号曲线，但这些曲线的振幅呈现出意外的温度依赖性，这可能是深入理解所观测到的声磁效应的关键。
英文摘要：
The current efforts striving to develop new ways of data manipulation are aimed at ultrafast control of magnetization in magnetic materials, as well as at inducing magnetic moments in diamagnetics. We demonstrate that in the diamagnetic quantum paraelectric KTaO$_3$, the electric field of circularly polarized THz pulses with an amplitude of $\sim 300\,$kV/cm induces a transient magnetic-like response by resonantly exciting its degenerate soft polar phonon. This phonon-mediated response was measured using the THz pump---optical probe technique via the time-resolved magneto-optic Faraday effect. Our detection scheme was set up to cancel out the major part of the electro-optic Kerr effect which also usually significantly contributes to the transient response. The Kerr-effect-related signal was further suppressed by subtracting the experimental data related to oppositely circularly polarized THz radiation. Thus, we were able to unambiguously identify a temperature-dependent magnetic-like behavior of the KTaO$_3$ crystal manifested by the extracted Faraday rotation. We developed a theoretical model describing well quantitatively the measured curves of the transient Faraday effect signal. However, their amplitudes exhibit an unexpected temperature dependence, which might be a key to a deeper understanding of the observed phonomagnetic effect.
