Conductance fluctuations in chaotic bilayer graphene quantum dots

Previous studies of quantum chaotic scattering established a connection between classical dynamics and quantum transport properties: integrable or mixed classical dynamics can lead to sharp conductance fluctuations but chaos is capable of smoothing out the conductance variations. Relativistic quantum transport through single layer graphene systems, for which the quasiparticles are massless Dirac fermions, exhibits this classical-quantum correspondence, but sharp conductance fluctuations persist to certain extent even when the classical system is fully chaotic. An open issue concerns about the effect of finite mass on relativistic quantum transport. To address this issue, we study quantum transport in chaotic bilayer graphene quantum dots for which the quasiparticles have a finite mass. An interesting phenomenon is that, when traveling along the classical ballistic orbit, the quasiparticle tends to hop back and forth between the two layers, exhibiting a Zitterbewegunglike effect. We find signatures of abrupt conductance variations, indicating that the mass has has little effect on relativistic quantum transport. In solid state electronic devices based on Dirac materials, sharp conductance fluctuations are thus expected, regardless of whether the quasiparticle is massless or massive and whether there is chaos in the classical limit.