Quantum Oscillations in Weyl and Dirac Semimetal Ultra-Thin Films

TL;DR

This paper demonstrates that ultra-thin films of Weyl and Dirac semimetals under strong in-plane magnetic fields form a unique two-dimensional Fermi liquid with highly anisotropic Fermi surfaces, leading to novel quantum oscillation phenomena.

Contribution

It introduces a new two-dimensional Fermi liquid state in Weyl and Dirac semimetal thin films induced by in-plane magnetic fields, highlighting the anisotropic Fermi surface and unusual quantum oscillations.

Findings

Fermi surface becomes strongly anisotropic under magnetic field.

Quantum oscillation frequencies depend on magnetic field orientation.

Potential experimental observation in Cd3As2, Na3Bi, and TaAs.

Abstract

We show that a thin film of Weyl or Dirac semimetal with a strong in-plane magnetic field becomes a novel 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 the 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 Cd$_3$As$_2$, Na$_3$Bi, and TaAs.