▎ 摘　　要

We investigate edge magnetoplasmons in semi-infinite graphene sheets. Similar to an ordinary two-dimensional electron system (2DES), at zero temperature graphene sheets exhibit two magnetoplasmon branches, a higher-energy one starting at the n = 1 Landau level (cyclotron frequency) and a lower-energy edge branch starting at zero frequency. However, in contrast to a 2DES with parabolic dispersion, at nonzero temperatures an extra magnetoplasmon branch arises at the n = 1 Landau level and has the same edge current rotation as the lower-energy branch.