Extrinsic orbital Hall effect and orbital relaxation in mesoscopic devices
Phys. Rev. B 114, 214401 – Published 1 October, 2026
DOI: https://doi.org/10.1103/79yg-jg9p
Abstract
Despite recent advances in orbitronics, the influence of disorder on the orbital Hall effect and orbital relaxation mechanisms remains poorly understood. In this work, we numerically investigate the role of disorder in orbital transport in mesoscopic two-dimensional square lattices hosting atomic orbitals that carry orbital angular momentum. Using the Landauer–Büttiker formalism in both square and rectangular device geometries, we study disorder-induced orbital Hall current generation and orbital relaxation on equal footing. We find that disorder can strongly enhance the orbital Hall response, with a disorder scaling consistent with a skew-scattering-like regime in the diffusive limit. The main calculations use a uniformly distributed Anderson potential, while additional calculations with a symmetrized disorder distribution, for which all odd moments vanish, produce essentially the same behavior. This response therefore differs from the conventional skew-scattering mechanism known from the anomalous Hall effect. In addition, we show that the orbital propagation length extracted from the spatial decay of the orbital current can extend over hundreds of lattice spacings, in stark contrast to recent theoretical works predicting orbital relaxation over only a few atomic spacings. We attribute this robustness to the two-dimensional nature of the system, where efficient orbital relaxation channels are strongly restricted, leading to long-ranged orbital transport despite substantial disorder.
