title: Transport evidence for Fermi-arc-mediated chirality transfer in the Dirac semimetal Cd3As2.
abstract: The dispersion of charge carriers in a metal is distinctly different from that of free electrons owing to their interactions with the crystal lattice. These interactions may lead to quasiparticles mimicking the massless relativistic dynamics of high-energy particle physics, and they can twist the quantum phase of electrons into topologically non-trivial knots-producing protected surface states with anomalous electromagnetic properties. These effects intertwine in materials known as Weyl semimetals, and in their crystal-symmetry-protected analogues, Dirac semimetals. The latter show a linear electronic dispersion in three dimensions described by two copies of the Weyl equation (a theoretical description of massless relativistic fermions). At the surface of a crystal, the broken translational symmetry creates topological surface states, so-called Fermi arcs, which have no counterparts in high-energy physics or conventional condensed matter systems. Here we present Shubnikov-de Haas oscillations in focused-ion-beam-prepared microstructures of Cd3As2 that are consistent with the theoretically predicted 'Weyl orbits', a kind of cyclotron motion that weaves together Fermi-arc and chiral bulk states. In contrast to conventional cyclotron orbits, this motion is driven by the transfer of chirality from one Weyl node to another, rather than momentum transfer of the Lorentz force. Our observations provide evidence for direct access to the topological properties of charge in a transport experiment, a first step towards their potential application.
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.|Max Planck Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187 Dresden, Germany.
authors.forename: Philip J W
authors.initials: PJ
authors.lastname: Moll
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Nityan L
authors.initials: NL
authors.lastname: Nair
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.|Max Planck Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187 Dresden, Germany.
authors.forename: Toni
authors.initials: T
authors.lastname: Helm
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Potter
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Itamar
authors.initials: I
authors.lastname: Kimchi
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Ashvin
authors.initials: A
authors.lastname: Vishwanath
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.|Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: James G
authors.initials: JG
authors.lastname: Analytis