Breakdown of the drift-diffusion model for transverse spin transport in a disordered Pt film

Published

October 25, 2023

Author(s)

Kirill Belashchenko, Giovanni G. Baez Flores, Wuzhang Fang, Alexei Kovalev, Mark van Schilfgaarde, Mark Stiles, Paul M. Haney

Abstract

Spin accumulation and spin current profiles are calculated for a disordered Pt film subjected to an in-plane electric current within the nonequilibrium Green function approach. In the bulklike region of the sample, this approach captures intrinsic spin Hall effect found in other calculations. Near the surfaces, the results reveal qualitative differences with the results of the spin-diffusion model, even when the boundary conditions are modified to try to account for them. One difference is that the effective spin-diffusion length for transverse spin transport is significantly different from its longitudinal counterpart and is similar to the mean-free path. This feature may be generic for spin currents generated via the intrinsic spin-Hall mechanism because of the differences in transport mechanisms compared to longitudinal spin transport. Orbital accumulation in the Pt film is only significant in the immediate vicinity of the surfaces and has a small component penetrating into the bulk only in the presence of spin-orbit coupling, as a secondary effect induced by the spin accumulation.

Citation

Physical Review B

Volume

108

Issue

14

Pub Type

Journals

Download Paper

https://doi.org/10.1103/PhysRevB.108.144433

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Keywords

spintronics, spin Hall effect, spin-orbit-torque, spin transport, electronic structure, spin accumulation, nonequilibrium Green, spin diffusion function

Citation

Belashchenko, K. , Baez Flores, G. , Fang, W. , Kovalev, A. , van Schilfgaarde, M. , Stiles, M. and Haney, P. (2023), Breakdown of the drift-diffusion model for transverse spin transport in a disordered Pt film, Physical Review B, [online], https://doi.org/10.1103/PhysRevB.108.144433, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=956438 (Accessed February 6, 2025)