Enhancement of Spin-charge Conversion in Dilute Magnetic Alloys by Kondo Screening

Abstract

We derive a kinetic theory capable of dealing both with large spin-orbit coupling and Kondo screening in dilute magnetic alloys. We obtain the collision integral non-perturbatively and uncover a contribution proportional to the momentum derivative of the impurity scattering S-matrix. The latter yields an important correction to the spin diffusion and spin-charge conversion coefficients, and fully captures the so-called side-jump process without resorting to the Born approximation (which fails for resonant scattering), or to otherwise heuristic derivations. We apply our kinetic theory to a quantum impurity model with strong spin-orbit, which captures the most important features of Kondo-screened Cerium impurities in alloys such as La${}_{1-x}$Cu${}_6$. We find 1) a large zero-temperature spin Hall conductivity that depends solely on the Fermi wave number and 2) a transverse spin diffusion mechanism that modifies the standard Fick's diffusion law. Our predictions can be readily verified by standard spin-transport measurements in metal alloys with Kondo impurities.

5 + 25 pages, 2 figures

References in corpus (7)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Topological Mott Insulators
• A conductive topological insulator with colossal spin Hall effect for ultra-low power spin-orbit-torque switching
• Topological Mott insulator in three-dimensional systems with quadratic band touching
• Giant spontaneous Hall effect in a nonmagnetic Weyl-Kondo semimetal
• Enhanced spin Hall effect by resonant skew scattering in orbital-selective Kondo effect
• Weyl-Kondo semimetals in nonsymmorphic systems