AI 中文总结
研究共线反铁磁体中NRSS的动态控制难题，利用密度泛函理论和非线性声子学，推导对称标准确定能激活或放大NRSS的声子模式，通过对NiO和LaFeO₃实验，实现超快可逆控制，放大NRSS，确立非线性声子学为操纵自旋分裂反铁磁相的通用途径。
AI 中文摘要
共线反铁磁体中的非相对论自旋分裂（NRSS）为高频自旋电子学提供了一条免受杂散场影响的途径，但其动态控制一直难以实现。我们使用密度泛函理论（DFT）和非线性声子学证明，太赫兹激光脉冲可以在皮秒时间尺度上实现反铁磁体中NRSS的超快、可逆控制。我们推导了两个对称标准，考虑声子和磁波矢兼容性以及序参量奇偶性，以确定哪些拉曼活性声子模式可以激活或放大NRSS。将这些规则应用于NiO和LaFeO₃，我们表明在11.08 THz处对红外活性模式的共振驱动通过双二次非谐耦合将自旋简并的NiO瞬态转换为NRSS状态，产生约40 meV的时间平均自旋分裂。在LaFeO₃中，选择性激发将现有的NRSS放大了约100%。在这两种情况下，诱导的自旋分裂都伴随着通过磁光克尔效应可检测到的瞬态SOC诱导净矩。这个框架将非线性声子学确立为一种超快操纵自旋分裂反铁磁相的通用途径，远远超出了静态应变的范围。
英文摘要
Nonrelativistic spin splitting (NRSS) in collinear antiferromagnets offers a route to high-frequency spintronics immune to stray fields, but its dynamic control has remained elusive. We demonstrate, using density functional theory (DFT) and nonlinear phononics, that THz laser pulses can achieve ultrafast, reversible control of NRSS on picosecond timescales in antiferromagnets. We derive two symmetry criteria, accounting for phonon and magnetic wavevector compatibility and order-parameter parity, to identify which Raman-active phonon modes can activate or amplify NRSS. Applying these rules to NiO and LaFeO$_3$, we show that resonant driving of an infrared-active mode at 11.08 THz transiently converts spin-degenerate NiO into an NRSS state via biquadratic anharmonic coupling, generating a time-averaged spin splitting of $\sim$40 meV. In LaFeO$_3$, selective excitation amplifies the existing NRSS by about 100%. In both cases, the induced spin splitting is accompanied by a transient SOC-induced net moment detectable via the magneto-optical Kerr effect. This framework establishes nonlinear phononics as a general route for ultrafast manipulation of spin-split antiferromagnetic phases well beyond the reach of static strain.
Comments7 pages, 5 figures
