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.

13 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