Motivated by the need to understand current-induced magnetization dynamics at the nanoscale, we have developed a formalism, within the framework of Keldysh Green function approach, to study the current-induced dynamics of a ferromagnetic (FM) nanoisland overlayer on a spin-orbit-coupling (SOC) Rashba plane. In contrast to the commonly employed classical micromagnetic LLG simulations the magnetic moments of the FM are treated {\it quantum mechanically}. We obtain the density matrix of the whole system consisting of conduction electrons entangled with the local magnetic moments and calculate the effective damping rate of the FM. We investigate two opposite limiting regimes of FM dynamics: (1) The precessional regime where the magnetic anisotropy energy (MAE) and precessional frequency are smaller than the exchange interactions, and (2) The local spin-flip regime where the MAE and precessional frequency are comparable to the exchange interactions. In the former case, we show that due to the finite size of the FM domain, the \textquotedblleft Gilbert damping\textquotedblright does not diverge in the ballistic electron transport regime, in sharp contrast to Kambersky's breathing Fermi surface theory for damping in metallic FMs. In the latter case, we show that above a critical bias the excited conduction electrons can switch the local spin moments resulting in demagnetization and reversal of the magnetization. Furthermore, our calculations show that the bias-induced antidamping efficiency in the local spin-flip regime is much higher than that in the rotational excitation regime.
Nonlocal damping of spin waves in a magnetic insulator induced by normal, heavy, or altermagnetic metallic overlayer: A Schwinger-Keldysh field theory approach
Time-retarded damping and magnetic inertia in the Landau-Lifshitz-Gilbert equation self-consistently coupled to electronic time-dependent nonequilibrium Green functions
Reply to the Comment on "Negative Landau damping in bilayer graphene"
在这里，我们解决了Svintsov和Ryzhii [arXiv：1812.03764]对我们关于石墨烯中的负朗道阻尼的文章[Phys. Rev. Lett. 119，133901（2017）]。我们证明，由于动力学和正则动量之间的差异，漂移电流偏置的石墨烯的导电性是由一个伽利略变换时，电子-电子相互作用占主导地位，并迫使电子气以恒定的速度移动，类似于一个移动的介质。此外，它表明，在石墨烯的非局部效应既不排除一个负的朗道阻尼，也没有出现在石墨烯平台的不稳定性。
Spin pumping damping and magnetic proximity effect in Pd and Pt spin-sink layers
我们研究了顺磁层（Pd，Pt）与铁磁Ni $_{81}$ Fe $_{19}$薄膜直接和间接接触时所产生的自旋泵浦阻尼。我们发现在直接接触Ni $_{81}$ Fe $_{19}$ /（Pd，Pt）结中，界面相关的吉尔伯特阻尼增强$Δα$与重金属自旋吸收层厚度t $_\textrm{N}$近似线性相关，而当Ni $_{81}$ Fe $_{19}$和（Pd，Pt）被\unit [3]{nm} Cu隔开时，则观察到指数相关.我们属性的准线性厚度依赖性的存在下，在Pt，Pd附近的界面与Ni $_{81}$ Fe $_{19}$，量化使用X-射线磁性圆二色性（XMCD）测量的感应力矩。我们的结果表明，在这些系统中，纯自旋流的散射是构型相关的，不能用单一的特征长度来描述。
Control of out-of-plane anti-damping spin torque with a canted ferromagnetic spin source
Cornell University（康奈尔大学）；University of California, Berkeley（加州大学伯克利分校）；University of Wisconsin-Madison（威斯康星大学麦迪逊分校）；Tsinghua University（清华大学）；Rice University（莱斯大学）
Spintronics meets nonadiabatic molecular dynamics: Geometric spin torque and damping on noncollinear classical magnetism due to electronic open quantum system
Observation of Orbit-Orbit Torques: Highly Efficient Torques on Orbital Moments Induced by Orbital Currents
School of Materials Science and Engineering, Beihang University（北京航空航天大学材料科学与工程学院）；State Key Laboratory of Tropic Ocean Engineering Materials and Materials Evaluation, Beihang University（北京航空航天大学热带海洋工程材料与材料评估国家重点实验室）
