▎ 摘　　要

We observed commensurability magnetoresistance arising from ballistic electron transport in a triangular antidot lattice of high-mobility graphene. For both the monolayer and bilayer, magnetoresistance peaks were observed at the commensurability magnetic fields of the cyclotron orbit with an antidot lattice. This condition was approximately unchanged for massless and massive Dirac fermions. The peaks appeared when the carrier mean free path was roughly larger than the lattice constant of the antidot, which indicates that the effect stems from the short-range characteristics of the carrier's scattering with antidots. We also found that the magnitude of the commensurability peak diminished with changing the gate voltages to the charge neutrality point. This arose from the screening of the charged impurity in graphene, which is dependent on the carrier density.