In Weyl semimetals the application of parallel electric and magnetic fields leads to valley polarization -- an occupation disbalance of valleys of opposite chirality -- a direct consequence of the chiral anomaly. In this work, we present numerical tools to explore such nonequilibrium effects in spatially confined three-dimensional systems with a variable disorder potential, giving exact solutions to leading order in the disorder potential and the applied electric field. Application to a Weyl-metal slab shows that valley polarization also occurs without an external magnetic field as an effect of chiral anomaly "trapping": Spatial confinement produces chiral bulk states, which enable the valley polarization in a similar way as the chiral states induced by a magnetic field. Despite its finite-size origin, the valley polarization can persist up to macroscopic length scales if the disorder potential is sufficiently long ranged, so that direct inter-valley scattering is suppressed and the relaxation then goes via the Fermi-arc surface states.
Authors / Affiliations: mappings to Contributors and OrganizationsSee all Organizations.
- 1 Institut Català de Nanociència i Nanotecnologia / Catalan Institute of Nanoscience and Nanotechnology [ICN2]
- 2 Instituut Lorentz / Lorentz Institute
- 3 Technische Universiteit Delft / Delft University of Technology [TU Delft]
- 4 Freie Universität Berlin / Freie Universität Berlin [FU Berlin]
- Deutsche Forschungsgemeinschaft / German Research FoundationDeutsche Forschungsgemeinschaft [DFG]
- European Research Council [ERC]
- Horizon 2020 (through Organization: European Commission [EC])
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek / Netherlands Organisation for Scientific Research [NWO]