Spin conductance, dynamic spin stiffness and spin diffusion in itinerant magnets
Abstract
We discuss analogies between the charge- and spin response functions of itinerant magnets. We show that the spin-analog of the charge stiffness is not given by the usual spin stiffness rho_s, but by the dynamic spin stiffness D_s, which is obtained from the dynamic spin conductance G_s (omega) in the limit of vanishing frequency omega. The low-frequency behavior of G_s (omega) is used to define ideal spin conductors, normal spin conductors, and spin insulators. Assuming diffusive spin dynamics, we show that the spin diffusion coefficient is proportional to lim_{omega rightarrow 0} {Re} {G}_s (omega). We exploit this fact to develop a new extrapolation scheme for the spin diffusion coefficient in the paramagnetic phase of the Hubbard model.
Keywords
Cite
@article{arxiv.cond-mat/9709316,
title = {Spin conductance, dynamic spin stiffness and spin diffusion in itinerant magnets},
author = {Peter Kopietz},
journal= {arXiv preprint arXiv:cond-mat/9709316},
year = {2009}
}
Comments
Discussion of gauge invariance and difference between transverse and longitudinal response added. Accepted for publication in Phys. Rev. B