Quantum oscillations in Weyl and Dirac semimetal ultrathin films

We show that a Weyl or Dirac semimetal thin film with a strong in-plane magnetic field becomes a two-dimensional Fermi liquid with interesting properties. The Fermi surface in this system is strongly anisotropic, which originates from a combination of chiral bulk channels and Fermi arcs. The area enclosed by the Fermi surface depends strongly on the in-plane magnetic field component parallel to the Weyl/Dirac node splitting, which leads to unusual behavior in quantum oscillations when the magnetic field is tilted out of the plane. We estimate the oscillation frequencies and the regimes where such effects could be seen in Cd3As2, Na3Bi, and TaAs.