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.

Discussion of gauge invariance and difference between transverse and longitudinal response added. Accepted for publication in Phys. Rev. B

References in corpus (4)

• Integrability and ideal conductance at finite temperatures
• Evidence for ideal insulating/conducting state in a 1D integrable system
• Spin diffusion of the t-J model
• Thouless number and spin diffusion in quantum Heisenberg ferromagnets

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• Phase Diagram and Magnetic Excitations of Anisotropic Spin-One Magnets
• Spin dynamics in lightly doped La${}_{2-x}$Sr${}_x$CuO${}_4$: Relaxation function within the $t-J$ model
• Charge and spin Drude weight of the one-dimensional extended Hubbard model at quarter-filling
• Spin Diffusion in Double-Exchange Manganites
• Spin dynamics in paramagnetic diluted magnetic semiconductors
• Spin diffusion and spin conductivity in the 2d Hubbard model
• Criticality in coupled quantum spin-chains with competing ladder-like and two-dimensional couplings
• Spin diffusion of lattice fermions in one dimension