Influence of a Gaussian nanobubble on quantum Hall conductance across a p-n junction in graphene*

Structural deformations in graphene can emerge during the fabrication processes. Although the nanobubbles in graphene has a capability to be applied in valleytronics and nano electromechanics, they also act as disorders causing inelastic scatterings in Dirac fermion transport. It is important to locate where the nanobubbles are formed in graphene surface not only for exploiting them to applications but also for avoiding them to acheive ballistic transport. Here, we report a theoretical investigation of influence of a Gaussian nanobubble on quantum Hall conductance with a p-n junction in graphene, showing strain-induced conductance oscillations as the position and strain strength of the Gaussian nanobubble vary. We reveal that the reported conductance oscillations stem from the rotation of valley isospin along the p-n junction interface. Due to the pseudo-magnetic field produced by the Gaussian nanobubble, there are localized states for given strain strengths, and Fano resonances can appear in the quantum Hall conductance as a consequence of coupline between the localized and extended states.