Quantum Hall States in Bilayer Graphene
Recently graphene has become one of the hottest topics in both theoretical and experimental condensed matter physics. In this talk, I will discuss a theory regarding the quantum Hall states (QHS) of the bilayer graphene. Using this theory, I will show that there exist two phases in the $nu=0$ QHS of the bilayer: one spin-polarized phase and another layer-polarized phase. It is also shown that the phase separation line and energy gap in these phases scale linearly with the magnetic field $B$. I then extend the discussion to QHS of other filling factors $nu=1,2,3$ and $4$. These theoretical results are compared with currently known experiments in bilayer graphene and reasonable agreements are found. I will also try to explain some connection between this theory and theories originated from other fields of physics.