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Chiral Anomaly Trapped in Weyl Metals: Nonequilibrium Valley Polarization at Zero Magnetic Field

by Pablo M. Perez-Piskunow, Nicandro Bovenzi, Anton R. Akhmerov, Maxim Breitkreiz

Submission summary

As Contributors: Anton Akhmerov · Maxim Breitkreiz · Pablo M. Perez-Piskunow
Arxiv Link: https://arxiv.org/abs/2104.10059v2 (pdf)
Code repository: https://zenodo.org/record/4704325
Date accepted: 2021-08-16
Date submitted: 2021-07-14 05:58
Submitted by: Breitkreiz, Maxim
Submitted to: SciPost Physics
Academic field: Physics
Specialties:
  • Condensed Matter Physics - Theory
Approach: Theoretical

Abstract

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.

Published as SciPost Phys. 11, 046 (2021)



Author comments upon resubmission

Dear Editor,

Thank you for considering our manuscript. We were pleased to find that
both referees recommend publication and have given useful suggestions for minor
changes, which we implemented in the new version of the manuscript and address below.

Sincerely,
Pablo M. Perez-Piskunow, Nicandro Bovenzi, Anton R. Akhmerov, and Maxim Breitkreiz

List of changes

- introduction section has been rewritten to extend the review of the role of the valley degree of freedom, disorder, and finite-size effects
- added numerical values of particle numbers in the caption of Fig. 4
- added a sentence at the end of section V
- third and second to last paragraphs in the conclusion section have been rewritten
- added 14 new references [5, 7, 18-25, 28, 37-39]
- minor typos have been corrected

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