From integrability to chaos in bilayer graphene quantum devices

Bilayer graphene exhibits a trigonally warped Fermi surface at low energies due to the interlayer hopping. Here, we demonstrate that the interplay between the device geometry and the anisotropic Fermi surface leads to a sharp transition from integrability to chaos upon rotation of the device respect to the underlying lattice. We observe this transition in level spacing statistics and in the structure of eigenfunctions. In general, our results establish bilayer graphene quantum devices as a versatile platform not only for investigating quantum nature of chaos, but also highlight how geometry and band structure anisotropy can be experimentally exploited to control quantum behaviors.