Work

Extrinsic Orbital Hall Effect: Orbital Skew Scattering and Crossover between Diffusive and Intrinsic Orbital Transport

Year: 2025

Type: article

Abstract: Despite the recent success of identifying experimental signatures of the orbital Hall effect (OHE), the research on the microscopic mechanisms behind this unique phenomenon is still in its infancy. Here, using a gapped 2D Dirac material as a model system of the OHE, we develop a microscopic theory of orbital transport which captures extrinsic disorder effects nonperturbatively. We show that it predicts several hitherto unknown effects, including (i) a strong dependence of the orbital Hall conductivity with the strength and symmetry of the impurity scattering potential, and (ii) a smooth crossover from intrinsic to extrinsic OHE as a function of the Fermi energy and impurity density. In contrast to previous (perturbative) studies, the OHE is found to exhibit bona fide diffusive behavior in the dilute impurity limit, which we trace back to the dominance of skew scattering-type processes. More generally, we argue that the newly unveiled orbital skew scattering mechanism governs the diffusive OHEs of a large class of 2D materials even when the crystal structure is inversion symmetric. Our work unveils the crucial nature of nonperturbative vertex corrections for a complete description of orbital transport and confirms common short-range impurities as key enablers of the OHE.

Source: Physical Review Letters

DOI: 10.1103/physrevlett.134.136201

Authors: Alessandro Veneri, Tatiana G. Rappoport, Aires Ferreira

Institutions: University of York, International Iberian Nanotechnology Laboratory, Centro de Física das Universidades do Minho e do Porto

Language: English

Topic: Topological Materials and Phenomena

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: Engineering and Physical Sciences Research Council, Fundação para a Ciência e a Tecnologia