  In a Weyl orbit, the Fermi arc surface states on opposite surfaces of the
topological semimetal are connected through the bulk Weyl or Dirac nodes.
Having a real-space component, these orbits accumulate a sample-size-dependent
phase. Following recent work on the three-dimensional Dirac semimetal cadmium
arsenide (Cd3As2), we have sought evidence for this thickness-dependent effect
in quantum oscillations and quantum Hall plateaus in (112)-oriented Cd3As2 thin
films grown by molecular beam epitaxy. We compare quantum transport in films of
varying thickness at apparently identical gate-tuned carrier concentrations and
find no clear dependence of the relative phase of the quantum oscillations on
the sample thickness. We show that small variations in carrier densities,
difficult to detect in low-field Hall measurements, lead to shifts in quantum
oscillations that are commensurate with previously reported phase shifts.
Future claims of Weyl orbits based on the thickness dependence of quantum
transport data require additional studies that demonstrate that these competing
effects have been disentangled.
