Quantum Oscillations in the Zeroth Landau Level: Serpentine Landau Fan and the Chiral Anomaly
Trithep Devakul, Yves H. Kwan, S. L. Sondhi, S. A. Parameswaran
Abstract
We identify an unusual mechanism for quantum oscillations in nodal semimetals, driven by a single pair of Landau levels periodically closing their gap at the Fermi energy as a magnetic field is varied. These "zero Landau level" quantum oscillations (ZQOs) appear in the nodal limit where the zero-field Fermi volume vanishes and have distinctive periodicity and temperature dependence. We link the Landau spectrum of a two-dimensional (2D) nodal semimetal to the Rabi model, and show by exact solution that, across the entire Landau fan, pairs of opposite-parity Landau levels are intertwined in a "serpentine" manner. We propose 2D surfaces of topological crystalline insulators as natural settings for ZQOs. In certain 3D nodal semimetals, ZQOs lead to oscillations of anomaly physics. We propose a transport measurement capable of observing such oscillations, which we demonstrate numerically.