We study the quantum-critical properties of antiferromagnetism in graphene at T=0 within mean-field (MF) theory. The resulting exponents differ from the conventional MF exponents, describing finite-temperature transitions. Motivated by this, we have developed the MF theory of general gapless phases with density of states ρ (ε) ∼ |ε| r, r>-1, with the interaction as control parameter. For r>2, the conventional MF exponents à la Landau are recovered, while for -1<r<2, the exponents vary significantly with r. The critical interaction is finite for r>0, therefore no weak-coupling solution exists in this range. This generalizes the results on quantum criticality of the gapless Kondo systems to bulk correlated phases.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Oct 11 2010|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics