▎ 摘　　要

We report markedly different transport properties of ABA- and ABC-stacked trilayer graphenes. Our experiments in double-gated trilayer devices provide evidence that a perpendicular electric field opens an energy gap in the ABC trilayer, while it causes the increase of a band overlap in the ABA trilayer. In a perpendicular magnetic field, the ABA trilayer develops quantum Hall plateaus at filling factors of v = 2,4,6, ... with a step of Delta v = 2, whereas the inversion-symmetric ABC trilayer exhibits plateaus at v = 6 and 10 with fourfold spin and valley degeneracy.