Twisted Fermi surface of a thin-film Weyl semimetal

Bovenzi, N.; Breitkreiz, Maxim; O’Brien, Thomas E.; Tworzydło, J.; Beenakker, C. W. J.

doi:10.1088/1367-2630/aaaa90

Cited by 32 publications

(24 citation statements)

References 32 publications

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“…For a system with surfaces at z = 1 and z = W , we assume that the surface at z = W displays an opposite polarization with respect to the one in z = 1 (as suggested by our numerical results based on the model (II.1), see also Ref. 34). In this case:…”

Section: Bulk Conductancementioning

confidence: 99%

Field theory approach to the quantum transport in Weyl semimetals

et al. 2019

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We analyze the structure of the surface states and Fermi arcs of Weyl semimetals as a function of the boundary conditions parameterizing the Hamiltonian self-adjoint extensions of a minimal model with two Weyl points. These boundary conditions determine both the pseudospin polarization of the system on the surface and the shape of the associated Fermi arcs. We analytically derive the expectation values of the density profile of the surface current, we evaluate the anomalous Hall conductivity as a function of temperature and chemical potential and we discuss the surface current correlation functions and their contribution to the thermal noise. Based on a lattice variant of the model, we numerically study the surface states at zero temperature and we show that their polarization and, consequently, their transport properties, can be varied by suitable Zeeman terms localized on the surface. We also provide an estimate of the bulk conductance of the system based on the Landauer-Büttiker approach. Finally, we analyze the surface anomalous thermal Hall conductivity and we show that the boundary properties lead to a correction of the expected universal thermal Hall conductivity, thus violating the Wiedemann-Franz law.arXiv:1907.01337v1 [cond-mat.mes-hall]

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Section: Bulk Conductancementioning

confidence: 99%

Field theory approach to the quantum transport in Weyl semimetals

et al. 2019

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“…[24]. The resulting anisotropy and the topologically protected crossing between electron and hole Fermi surfaces may lead to novel magneto-electric and transport properties [51,52]. In this Supplemental Material we examine the symmetries of the 3D Lieb lattice, analyze the topologically protected Fermi arcs appearing on its surfaces, and we illustrate the optical lattice potential.…”

Section: Discussionmentioning

confidence: 99%

Geometrically protected triple-point crossings in an optical lattice

2018

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We show how to realize topologically protected crossings of three energy bands, integer-spin analogs of Weyl fermions, in three-dimensional optical lattices. Our proposal only involves ultracold atom techniques that have already been experimentally demonstrated and leads to isolated triplepoint crossings (TPCs) which are required to exist by a novel combination of lattice symmetries. The symmetries also allow for a new type of topological object, the type-II, or tilted, TPC. Our Rapid Communication shows that spin-1 Weyl points, which have not yet been observed in the bandstructure of crystals, are within reach of ultracold atom experiments. 2Weyl cones. Here, we take a different perspective and discuss TPCs which are constrained to appear due to the real-space geometry of the lattice. Hence we refer to them as geometrically protected TPCs.Our proposal is based on the experimental successes in the quantum simulation of gauge potentials in cold atom systems [30]. Ultracold gases trapped in optical lattices offer two ingredients which can be controlled with high arXiv:1711.10935v2 [cond-mat.mes-hall]

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“…coming from the boundary condition of the slab [30]. Throughout this work we assume W 1, in which case the solution for q can be divided into three groups: (i) the group of bulk states, given by the quasicontinuous set q = (n + 0.5)π/W , n = 0, 1, 2, .…”

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confidence: 99%

Parabolic Hall effect due to copropagating surface modes

Breitkreiz

2020

Phys. Rev. Research

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Real-space separations of countermoving states to opposite surfaces or edges are associated with different types of Hall effects, such as the quantum, spin, or the anomalous Hall effect. Some systems provide the possibility to separate a fraction of countermovers in a completely different fashion: surface states propagating all in the same direction, balanced by countermoving bulk states, realized, e.g., in Weyl metals with intrinsically or extrinsically broken inversion and time-reversal symmetries. In this Rapid Communication we show that these copropagating surface modes are associated with a specific Hall effect-a parabolic potential profile in the direction perpendicular to and in its magnitude linear in the applied field. While in two-dimensional (2D) systems the parabolic potential profile is directly measurable, in 3D the resulting voltage between the bulk and surface is measurable in the geometry of a hollow cylinder. Moreover, the parabolic Hall effect leads to characteristic signatures in the longitudinal conductivity.

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Twisted Fermi surface of a thin-film Weyl semimetal

Cited by 32 publications

References 32 publications

Field theory approach to the quantum transport in Weyl semimetals

Field theory approach to the quantum transport in Weyl semimetals

Geometrically protected triple-point crossings in an optical lattice

Parabolic Hall effect due to copropagating surface modes

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