▎ 摘　　要

The quantum Hall system in graphene possesses a unique character that the intrinsic Zeeman energy is precisely one half of the cyclotron energy since electrons obey the Dirac equation. Consequently, a single energy level contains up-spin and down-spin electrons belonging to different Landau levels. Since Coulomb interactions are different for electrons in different Landau levels, a remarkable consequence is derived that the effective Coulomb potential depends on spins in each energy level. (C)2007 Elsevier B.V. All rights reserved.