Canted antiferromagnetism and excitonic order in gated double-layer graphene

Abstract

We study the effects of the electron-electron interactions on the excitonic properties and charge-density modulations in the AB stacked double-layer (DL) graphene, placed in the external gate-potential $V$. The coexistence of the canted antiferromagnetic order and excitonic pairing gap has been studied with the help of the generalized Hubbard model. We calculate the chemical potential $\mu$, the average charge density difference between the layers $\delta \bar{n}$, the antiferromagnetic gap-function ${\Delta }_{\mathrm{AFM}}$ and the excitonic order parameters ${\Delta }_{\sigma }$ in the zero temperature limit. We found that the excitonic pairing order parameter has a larger energy scale than the canted antiferromagnetic gap-function. The charge neutrality, in the DL graphene system, occurs only in the absence of the external gate-potential $V$. Moreover, we have shown that the values of the antiferromagnetic gap-function ${\Delta }_{\mathrm{AFM}}$ and excitonic order parameter ${\Delta }_{\sigma }$ are always increasing at the large values of inter-layer Coulomb interaction, while they are decreasing for large values of the applied gate-potential $V$.

10 pages, 5 figures

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Cited by in corpus (1)

• Applied electric and magnetic field effects on the bandgap formation and antiferromagnetic ordering in AA-stacked Bilayer Graphene