Enhancement of Spin-Charge Conversion in Dilute Magnetic Alloys by Kondo Screening
Physical Review Letters 127, 176801 (2021)
Enhancement of Spin-Charge Conversion in Dilute Magnetic Alloys by Kondo Screening
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 nonperturbatively 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 CexLa1−xCu6. 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.
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- http://dx.doi.org/10.1103/PhysRevLett.127.176801
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- http://arxiv.org/abs/2008.10185