Quantum Critical Behaviour in a Graphene-like Model
Abstract
We present the first results of numerical simulations of a 2+1 dimensional fermion field theory based on a recent proposal for a model of graphene, consisting of N_f four-component Dirac fermions moving in the plane and interacting via an instantaneous Coulomb interaction. In the strong-coupling limit we identify a critical number of flavors N_fc=4.8(2) separating an insulating from a conducting phase. This transition corresponds to the location of a quantum critical point, and we use a fit to the equation of state for the chiral order parameter to estimate the critical exponents. Next we simulate N_f=2 corresponding to real graphene, and approximately locate a transition from strong to weak coupling behaviour. Strong correlations are evident in the weak-coupling regime.
Cite
@article{arxiv.0806.4877,
title = {Quantum Critical Behaviour in a Graphene-like Model},
author = {Simon Hands and Costas Strouthos},
journal= {arXiv preprint arXiv:0806.4877},
year = {2008}
}
Comments
14 pages, 6 figures