Popov A I, Gareeva Z V, Zvezdin A K
National Research University of Electronic Technology-MIET, 124498 Moscow, Russia.
Institute of Molecule and Crystal Physics, Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences, 450075 Ufa, Russia.
J Phys Condens Matter. 2024 Oct 11;37(2). doi: 10.1088/1361-648X/ad80ee.
A quantum theory of spin dynamics in the rare-earth orthoferrites excited by terahertz laser pulses is developed. The study demonstrates that dynamic magnetic configurations, triggered by a light pulse, exhibit stability even after the excitation source is ceased. The magnitude of post-excitation oscillations is linked to the ratio between the frequency of rare-earth ion excitations and the frequency of the external source. According to the analysis presented, dynamic response is significantly amplified when the system is exposed to ultrashort terahertz pulses. The physical characteristics of the oscillations emerging after the pulse are determined, and the factors governing their amplitude and phase are identified. The response signal is found to be dependent on the initial part of the pulse, specifically the half-period of the ultrashort light wave, while the subsequent part of the pulse contributes minimally to post-pulse magnetization dynamics. The findings highlight that in DyFeO, terahertz dynamics primarily result from the influence of the magnetic field of the light, leading to excitations of electrons from the ground state to low-lying electronic levels of Dyions. Additionally, the dynamic magnetoelectric effect excited by the electric field of the pulse is explored, revealing the emergence of odd magnetic modes.
发展了一种由太赫兹激光脉冲激发的稀土正铁氧体中自旋动力学的量子理论。该研究表明，由光脉冲触发的动态磁结构即使在激发源停止后仍表现出稳定性。激发后振荡的幅度与稀土离子激发频率和外部源频率之间的比率有关。根据所呈现的分析，当系统暴露于超短太赫兹脉冲时，动态响应会显著放大。确定了脉冲后出现的振荡的物理特性，并识别了控制其幅度和相位的因素。发现响应信号取决于脉冲的初始部分，特别是超短光波的半周期，而脉冲的后续部分对脉冲后磁化动力学的贡献最小。研究结果突出表明，在DyFeO中，太赫兹动力学主要源于光磁场的影响，导致电子从基态激发到Dy离子的低电子能级。此外，还探索了由脉冲电场激发的动态磁电效应，揭示了奇磁模式的出现。
