Warping-induced quantum scars in bilayer graphene

Prior studies on quantum scars have mainly focused on classically chaotic systems with isotropic dispersion. However, in bilayer graphene (BLG) device, interlayer hopping induces trigonal warping, giving rise to an anisotropic Fermi surface even at low energies, which subsequently influences the system’s dynamical behavior. In integrable BLG flakes, we find that the warping generates scars whose shapes depend sensitively on the orientation of the flake with respect to the underlying lattice. We further demonstrate that these scars are strongly connected to the geometry of the flake, and can be controlled by an external magnetic field. To clarify their origin, semiclassical ray tracing reveals that the anisotropic Fermi surface modifies the specular reflection law, thereby altering the positions and stabilities of trajectories. Our results illustrate that BLG provides an experimentally feasible platform for investigating the emergence of quantum scars in a controlled manner.