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arXiv · 1212.4716

Ferromagnetism in ABC-trilayer graphene

Richard Olsen·Ralph van Gelderen·C. Morais Smith
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Abstract

In this article we study the ferromagnetic behavior of ABC-stacked trilayer graphene. This is done using a nearest-neighbor tight-binding model, in the presence of long-range Coulomb interactions. For a given electron-electron interaction g and doping level n, we determine whether the total energy is minimized for a paramagnetic or ferromagnetic configuration of our variational parameters. The g versus n phase diagram is first calculated for the unscreened case. We then include the effects of screening using a simplified expression for the fermion bubble diagram. We show that ferromagnetism in ABC-trilayer graphene is more robust than in monolayer, in bilayer, and in ABA-trilayer graphene. Although the screening reduces the ferromagnetic regime in ABC-trilayer graphene, the critical doping level remains one order of magnitude larger than in unscreened bilayer graphene.

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Richard Olsen, Ralph van Gelderen, C. Morais Smith. 2012-12-19. Ferromagnetism in ABC-trilayer graphene. https://doi.org/10.1103/physrevb.87.115414

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