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Fractional Quantum Hall States of Dirac Electrons in Graphene

2006; American Physical Society; Volume: 97; Issue: 12 Linguagem: Inglês

10.1103/physrevlett.97.126801

1092-0145

Vadim M. Apalkov, Tapash Chakraborty,

Topological Materials and Phenomena

We have investigated the fractional quantum Hall states of Dirac electrons in a graphene layer in different Landau levels. The relativistic nature of the energy dispersion relation of electrons in graphene significantly modifies the interelectron interactions. This results in a specific dependence of the ground state energy and the energy gaps for electrons on the Landau-level index. For the valley-polarized states, i.e., at $\ensuremath{\nu}=1/m$, $m$ being an odd integer, the energy gaps have the largest values in the $n=1$ Landau level. For the valley-unpolarized states, e.g., for the $2/3$ state, the energy gaps are suppressed for $n=1$ as compared to those at $n=0$. For both $n=1$ and $n=0$, the ground state of the $2/3$ system is fully valley-unpolarized.