Phase diagram of insulating crystal and quantum Hall states in ABC-stacked trilayer graphene

Article

关键词: WEAK FERROMAGNETISM;    BILAYER GRAPHENE;    DIRAC FERMIONS;    BERRYS PHASE;   

DOI  :  10.1103/PhysRevB.86.125422

来源: SCIE

【 摘 要 】

In the presence of a perpendicular magnetic field, ABC-stacked trilayer graphene's chiral band structure supports a 12-fold degenerate N = 0 Landau level (LL). Along with the valley and spin degrees of freedom, the zeroth LL contains additional quantum numbers associated with the LL orbital index n = 0,1,2. Remote interlayer hopping terms and external potential difference Delta(B) between the layers lead to LL splitting by introducing a gap Delta(LL) between the degenerate zero-energy triplet LL orbitals. Assuming that the spin and valley degrees of freedom are frozen, we study the phase diagram of this system resulting from competition of the single particle LL splitting and Coulomb interactions within the Hartree-Fock approximation at integer filling factors. In some range [Delta(c,1)(LL), Delta(c,2)(LL)] of the gap Delta(LL), the uniform QH state is unstable to the formation of a crystal state at integer filling factors while outside of this range, the ground state is a uniform quantum Hall state where the electrons occupy the lowest unoccupied LL orbital index. The transition between the uniform and crystal states should be characterized by a Hall plateau transition as a function of Delta(LL) at a fixed filling factor. We also study the properties of this crystal state and discuss its experimental detection.

【 授权许可】

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