▎ 摘　　要

Carrier interactions on graphene are studied. The study shows that besides the well-known Coulomb repulsion between carriers, there also exist four-fermion interactions associated with the U-process, one of which attracts carriers in different valleys. We then calculate the contributions to the valley magnetic moment from vertex corrections and from four-fermion corrections explicitly. The relative contributions are -18% and 3%, respectively. Lastly we point out that we can mimic the heavy-quarkonium system by carrier interactions in graphene. Copyright (C) EPLA, 2010