Twisted Fermi surface of a thin-film Weyl semimetal

Abstract

The Fermi surface of a conventional two-dimensional electron gas is equivalent to a circle, up to smooth deformations that preserve the orientation of the equi-energy contour. Here we show that a Weyl semimetal confined to a thin film with an in-plane magnetization and broken spatial inversion symmetry can have a topologically distinct Fermi surface that is twisted into a $\mbox{figure-8}$ $-$ opposite orientations are coupled at a crossing which is protected up to an exponentially small gap. The twisted spectral response to a perpendicular magnetic field $B$ is distinct from that of a deformed Fermi circle, because the two lobes of a \mbox{figure-8} cyclotron orbit give opposite contributions to the Aharonov-Bohm phase. The magnetic edge channels come in two counterpropagating types, a wide channel of width $\beta l_m^2\propto 1/B$ and a narrow channel of width $l_m\propto 1/\sqrt{B}$ (with $l_m=\sqrt{\hslash /eB}$ the magnetic length and $\beta$ the momentum separation of the Weyl points). Only one of the two is transmitted into a metallic contact, providing unique magnetotransport signatures.

V4: 10 pages, 14 figures. Added figure and discussion about "uncrossing deformations" of oriented contours, plus minor corrections. Published in NJP

References in corpus (7)

• Weyl and Dirac Semimetals in Three Dimensional Solids
• Quantum-limited shot noise in graphene
• Discovery of Weyl fermion semimetals and topological Fermi arc states
• Weyl Metals
• Modern semiclassical theory of magnetic transport and breakdown
• Topo-fermiology
• Modern theory of magnetic breakdown

Cited by in corpus (19)

• Robust edge photocurrent response on layered Type II Weyl semimetal WTe2
• Towards Weyltronics: Realization of epitaxial NbP and TaP Weyl Semimetal thin films
• Landau levels, Bardeen polynomials and Fermi arcs in Weyl semimetals: the who's who of the chiral anomaly
• Geometrically protected triple-point crossings in an optical lattice
• Transmission and conductance across junctions of isotropic and anisotropic three-dimensional semimetals
• Transport, refraction and interface arcs in junctions of Weyl semimetals
• Theory of quantum oscillations in quasicrystals: Quantizing spiral Fermi surfaces
• Phonon-limited Transport and Fermi Arc Lifetime in Weyl Semimetals
• Surface photogalvanic effect in Weyl semimetals
• Three-dimensional graphdiyne as a topological nodal-line semimetal
• Phonon-induced magnetoresistivity of Weyl semimetal nanowires
• Field theory approach to the quantum transport in Weyl semimetals
• Phase shift of cyclotron orbits at type-I and type-II multi-Weyl nodes
• Magnetic breakdown spectrum of a Kramers-Weyl semimetal
• Lifshitz transitions and Weyl semimetals from a topological superconductor with supercurrent flow
• Quantum description of Fermi arcs in Weyl semimetals in a magnetic field
• Parabolic Hall Effect due to Co-Propagating Surface Modes
• Experimental study of transport properties of Weyl semimetal LaAlGe thin films grown by molecular beam epitaxy
• Chiral Anomaly Trapped in Weyl Metals: Nonequilibrium Valley Polarization at Zero Magnetic Field