Role of boundary conditions, topology, and disorder in the chiral magnetic effect in Weyl semimetals

Alavirad, Yahya; Sau, Jay D.

doi:10.1103/physrevb.94.115160

Cited by 19 publications

(25 citation statements)

References 50 publications

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“…The result for the average velocity of an ideal single Weyl node [Eq. (17)] can be confirmed in our numerical calculations. Since our calculation of the φ dispersion includes diagonalizing the tight-binding Hamiltonian, we have all the eigenstates of the system together with their corresponding eigenvalues.…”

Section: Numerical Resultssupporting

confidence: 83%

Chiral anomaly without Landau levels: From the quantum to the classical regime

Lee

Pixley

2018

Phys. Rev. B

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We study the chiral anomaly in disordered Weyl semimetals, where the broken translational symmetry prevents the direct application of Nielsen and Ninomiya's mechanism and disorder is strong enough that quantum effects are important. In the weak disorder regime, there exist rare regions of the random potential where the disorder strength is locally strong, which gives rise to quasilocalized resonances and their effect on the chiral anomaly is unknown. We numerically show that these resonant states do not affect the chiral anomaly only in the case of a single Weyl node. At energies away from the Weyl point, or with strong disorder where one is deep in the diffusive regime, the chiral Landau level itself is not well defined and the semiclassical treatment is not justified. In this limit, we analytically use the supersymmetry method and find that the Chern-Simons term in the effective action which is not present in nontopological systems gives rise to a nonzero average level velocity which implies chiral charge pumping. We numerically establish that the nonzero average level velocity serves as an indicator of the chiral anomaly in the diffusive limit. arXiv:1805.00485v2 [cond-mat.dis-nn]

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Section: Numerical Resultssupporting

confidence: 83%

Chiral anomaly without Landau levels: From the quantum to the classical regime

Lee

Pixley

2018

Phys. Rev. B

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“…The current in the Weyl cone of one chirality has to be canceled by a current in the Weyl cone of opposite chirality to ensure zero net current in equilibrium. The generation of an electrical current density j along an applied magnetic field B, the so-called chiral magnetic effect (CME) [7,8], has been observed as a dynamic, nonequilibrium phenomenon [9][10][11][12][13]-but it cannot be realized in equilibrium because of the fermion doubling [14][15][16][17][18][19][20][21][22][23][24].…”

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confidence: 99%

Superconductivity Provides Access to the Chiral Magnetic Effect of an Unpaired Weyl Cone

2017

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The massless fermions of a Weyl semimetal come in two species of opposite chirality, in two cones of the band structure. As a consequence, the current j induced in one Weyl cone by a magnetic field B [the chiral magnetic effect (CME)] is canceled in equilibrium by an opposite current in the other cone. Here, we show that superconductivity offers a way to avoid this cancellation, by means of a flux bias that gaps out a Weyl cone jointly with its particle-hole conjugate. The remaining gapless Weyl cone and its particle-hole conjugate represent a single fermionic species, with renormalized charge e Ã and a single chirality AE set by the sign of the flux bias. As a consequence, the CME is no longer canceled in equilibrium but appears as a supercurrent response ∂j=∂B ¼ AEðe Ã e=h 2 Þμ along the magnetic field at chemical potential μ.

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“…For future research it would interestering to investigate the influence of disorder and Coulomb interactions on the magnetovortical conductivities, which has already been explored for the chiral magnetic conductivity 65 .…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Magnetovortical and thermoelectric transport in tilted Weyl metals

Wurff

Stoof

2019

Phys. Rev. B

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We investigate how tilting affects the off-diagonal, dissipationless response of a pair of chirally imbalanced Weyl cones to various external perturbations. The pair of chirally imbalanced Weyl cones can be described as a chiral electron fluid, that can flow with a velocity field that contains vorticity. Upon applying an external magnetic field, we obtain the so-called magnetovortical linear-response matrix that relates electric and heat currents to the magnetic field (chiral magnetic effect) and the vorticity (chiral vortical effect). We show how this reponse matrix becomes anisotropic upon tilting the cones and determine its non-analytic long-wavelength behavior, as well as the corresponding AC response. In addition, we discuss how the tilt dependence of the electronic (or density-density) susceptibility introduces anisotropy in the dispersion relation of the sound-like excitations in the fluid of chiral fermions, which are known as chiral magnetic waves. In the case of an externally applied electric field and a temperature gradient, we find a Hall-like response in the electric and heat current density that is perpendicular to both the tilting direction and the perturbations. As the tilting direction forms a time-reversal symmetry breaking vector, a non-zero (heat) orbital magnetization manifests itself. We calculate the magnetization currents microscopically and elucidate how to subtract these contributions to obtain the transport currents.a In principle, there can be different Fermi velocities in all three directions. This anisotropy can however always be transformed away by an appropriate scaling of the momenta.

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Role of boundary conditions, topology, and disorder in the chiral magnetic effect in Weyl semimetals

Cited by 19 publications

References 50 publications

Chiral anomaly without Landau levels: From the quantum to the classical regime

Chiral anomaly without Landau levels: From the quantum to the classical regime

Superconductivity Provides Access to the Chiral Magnetic Effect of an Unpaired Weyl Cone

Magnetovortical and thermoelectric transport in tilted Weyl metals

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