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

TY - JOUR

T1 - Extrinsic Orbital Hall Effect

T2 - Orbital Skew Scattering and Crossover between Diffusive and Intrinsic Orbital Transport

AU - Veneri, Alessandro

AU - Rappoport, Tatiana G.

AU - Ferreira, Aires

N1 - © 2025 American Physical Society. This is an author-produced version of the published paper. Uploaded in accordance with the University’s Research Publications and Open Access policy.

PY - 2025/4/4

Y1 - 2025/4/4

N2 - 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.

AB - 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.

KW - orbital hall effect

KW - orbitronics

KW - transport

KW - condensed matter theory

U2 - 10.1103/PhysRevLett.134.136201

DO - 10.1103/PhysRevLett.134.136201

M3 - Letter

SN - 0031-9007

VL - 134

JO - Physical Review Letters

JF - Physical Review Letters

M1 - 136201

ER -