Interaction-induced enhancement of g-factor in graphene

• We study the effect of electron interaction on the spin-splitting and the g-factor in graphene in perpendicular magnetic field using the Hartree and Hubbard approximations within the Thomas-Fermi model. We found that the g-factor is enhanced in comparison to its free electron value g = 2 and oscillates as a function of the filling factor ѵ in the range 2 ≤ g∗ < 4 reaching maxima at even ѵ and minima at odd ѵ. We outline the role of charged impurities in the substrate, which are shown to suppress the oscillations of the g∗-factor. This effect becomes especially pronounced with the increase of the impurity concentration, when the effective g-factor becomes independent of the filling factor reaching a value of g∗ ≈ 2.3. A relation to the recent experiment is discussed.

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