Events in Physics

We consider the extended half-filled Hubbard model on the honeycomb lattice for second nearest neighbours interactions. Using a functional integral approach, we find that collective fluctuations suppress topological states and instead favour charge ordering, in agreement with previous numerical studies. However, we show that the critical point is not of the putative Dirac semimetal/Mott insulator variety. Due to the frustrated nature of the interactions, the charge-ordered ground state remains metallic with semi-Dirac excitations. We conjecture that this novel transition is not in the Gross-Neveu universality class.