Spin-rotation mode in a quantum Hall ferromagnet
Abstract
A spin-rotation mode emerging in a quantum Hall ferromagnet due to laser pulse excitation is studied. This state, macroscopically representing a rotation of the entire electron spin-system to a certain angle, is not microscopically equivalent to a coherent turn of all spins as a single-whole and is presented in the form of a combination of eigen quantum states corresponding to all possible S_z spin numbers. The motion of the macroscopic quantum state is studied microscopically by solving a non-stationary Schroedinger equation and by means of a kinetic approach where damping of the spin-rotation mode is related to an elementary process, namely, transformation of a `Goldstone spin exciton' to a `spin-wave exciton'. The system exhibits a spin stochastizationa mechanism (determined by spatial fluctuations of the Land'e g-factor) ensuring damping, transverse spin relaxation, but irrelevant to decay of spin-wave excitons and thus not involving longitudinal relaxation, i.e., recovery of the S_z number to its equilibrium value.
Keywords
Cite
@article{arxiv.1709.06811,
title = {Spin-rotation mode in a quantum Hall ferromagnet},
author = {S. Dickmann},
journal= {arXiv preprint arXiv:1709.06811},
year = {2020}
}
Comments
15 pages including a figure