Identification of the dominant precession damping mechanism in Fe, Co, and Ni by first-principles calculations

强关联巡游电子系统中的拉莫尔进动

Larmor precession in strongly correlated itinerant electron systems

本研究利用动力学平均场理论，结合沃德恒等式，研究了强关联巡游电子系统中磁场诱导的集体拉莫尔进动及其自旋波阻尼，为理解关联材料中的自旋动力学提供了新途径。

磁子 $φ$ 约瑟夫森结与同步进动

Magnonic $φ$ Josephson junctions and synchronized precession

本文理论上揭示了磁性结中固有的非局部阻尼在微波泵浦下能同步左右铁磁体的自旋进动，从而产生 $φ$ 约瑟夫森结的磁子类似物及磁子二极管整流效应。

Spin pumping and magnetization dynamics in ferromagnet-Luttinger liquid junctions

We study spin transport between a ferromagnet with time-dependent magnetization and a conducting carbon nanotube or quantum wire, modeled as a Luttinger liquid. The precession of the magnetization vector of the ferromagnet due for instance to an outside applied magnetic field causes spin pumping into an adjacent conductor. Conversely, the spin injection causes increased magnetization damping in the ferromagnet. We find that, if the conductor adjacent to the ferromagnet is a Luttinger liquid, spin pumping/damping is suppressed by interactions, and the suppression has clear Luttinger liquid powe…

Spin dynamics in (III,Mn)V ferromagnetic semiconductors: the role of correlations

We address the role of correlations between spin and charge degrees of freedom on the dynamical properties of ferromagnetic systems governed by the magnetic exchange interaction between itinerant and localized spins. For this we introduce a general theory that treats quantum fluctuations beyond the Random Phase Approximation based on a correlation expansion of the Green's function equations of motion. We calculate the spin susceptibility, spin--wave excitation spectrum, and magnetization precession damping. We find that correlations strongly affect the magnitude and carrier concentration depen…

Finite temperature damping of collective modes of a BCS-BEC crossover superfluid

A new mechanism is proposed to explain the puzzling damping of collective excitations, which was recently observed in the experiments of strongly interacting Fermi gases below the superfluid critical temperature on the fermionic (BCS) side of Feshbach resonance. Sound velocity, superfluid density and damping rate are calculated with effective field theory. We find that a dominant damping process is due to the interaction between superfluid phonons and thermally excited fermionic quasiparticles, in contrast to the previously proposed pair-breaking mechanism. Results from our effective model are…

Ultrafast light-induced magnetization dynamics in ferromagnetic semiconductors

We develop a theory of the magnetization dynamics triggered by ultrafast optical excitation of ferromagnetic semiconductors. We describe the effects of the strong carrier spin relaxation on the nonlinear optical response by using the Lindblad semigroup method. We demonstrate magnetization control during femtosecond timescales via the interplay between circularly polarized optical excitation, hole-spin damping, polarization dephasing, and the Mn-hole spin interactions. Our results show a light-induced magnetization precession and relaxation for the duration of the optical pulse.