Can bilayer graphene become a fractional metal?

Abstract

It is known that electron interactions can cause a perfect spin polarization of the Fermi surface of a metal. In such a situation only half of the non-interacting Fermi surface is available, and thus this phase is commonly referred to as a 'half-metal'. Here we argue that, in multi-band electronic systems with nesting, further 'fractionalization' of the Fermi surface is possible. Taking the AA bilayer graphene as a convenient test case, we demonstrate that, under suitable conditions imposed on the electron interactions, doped AA bilayer graphene can host a 'quarter-metal' state. In such a state, only one quarter of the non-interacting Fermi surface (Fermi contour) reaches the Fermi energy. At higher doping level, other 'fractional' metals can emerge. We briefly analyze the transport properties of these proposed phases.

arXiv comment13 pages, 1 pdf figure

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Cited by in corpus (10)

• Triplet superconductivity and spin density wave in biased AB bilayer graphene
• Antiferromagnetic ordering and excitonic pairing in the AA-stacked bilayer graphene
• Half-metal and other fractional metal phases in doped AB bilayer graphene
• Magic radius of AA bilayer graphene quantum dot
• Quasi-free-standing AA-stacked bilayer graphene induced by calcium intercalation of the graphene-silicon carbide interface
• Ordering in SU(4)-symmetric model of AA bilayer graphene
• Superconductivity and spin density wave in AA stacked bilayer graphene
• Ordered states in AB bilayer graphene in SU(4)-symmetric model
• Nesting-driven ferromagnetism of itinerant electrons
• Ordered states of undoped AB bilayer graphene: bias induced cascade of transitions