Regularization of a massless Dirac model to describe anomalous electromagnetic response of Weyl semimetals

Abstract

An unbounded massless Dirac model with two nondegenerate Dirac cones is the simplest model for Weyl semimetals, which show the anomalous electromagnetic response of chiral magnetic effect (CME) and anomalous Hall effect (AHE). However, if this model is naively used to analyze the electromagnetic response within a linear response theory, it gives the result apparently inconsistent with the persuasive prediction based on a lattice model. We show that this serious difficulty is related to the breaking of current conservation in the Dirac model due to quantum anomaly and can be removed if current and charge operators are redefined to include the contribution from the anomaly. We demonstrate that the CME as well as the AHE can be properly described using newly defined operators, and clarify that the CME is determined by the competition between the contribution from the anomaly and that from low-energy electrons.

5 pages

References in corpus (7)

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• Topological Weyl Semi-metal from a Lattice Model
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Cited by in corpus (9)

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• Comparative study of Weyl semimetal, topological and Chern insulators: thin-film point of view
• Persistent current due to a screw dislocation in Weyl semimetals: Role of one-dimensional chiral states
• Photoexcitation in two-dimensional topological insulators: Generating and controlling electron wavepackets in Quantum Spin Hall systems
• Regularized framework of a Weyl equation for describing a Weyl semimetal: Application to the case with a screw dislocation
• Gauge-invariant cutoff for Dirac electron systems with a vector potential
• Regularized continuum model of a Weyl semimetal for describing anomalous electromagnetic response