▎ 摘　　要

In a magnetic field graphene trilayers support a characteristic multiplet of 12 zero (energy) mode Landau levels with a threefold degeneracy in Landau orbitals. It was earlier noted for bilayer graphene that Coulombic vacuum fluctuations, specific to graphene, lift the orbital degeneracy of such zero-energy modes and that these "Lamb-shifted" orbital modes, with filling, get mixed via the Coulomb interaction. It is pointed out that an analogous orbital Lamb shift and mixing of zero-mode levels can also take place, with an enriched symmetry content, in ABC-stacked trilayer graphene, and its consequences are discussed in the light of experimental results. DOI: 10.1103/PhysRevB.87.085413