Gate-tunable regular and chaotic electron dynamics in ballistic bilayer graphene cavities

The dispersion of any given material is crucial for its charge carriers' dynamics. For all-electronic, gatedefined cavities in gapped bilayer graphene, we developed a trajectory-tracing algorithm aware of the material's electronic properties and details of the confinement. We show how the anisotropic dispersion of bilayer graphene induces chaotic and regular dynamics depending on the gate voltage, despite the high symmetry of the circular cavity. Our results demonstrate the emergence of nonstandard fermion optics solely due to anisotropic material characteristics.