Quantum critical Mott transition in triangular lattice Hubbard model

Using large-scale dynamical cluster quantum Monte Carlo simulations, we study the correlation-driven metal-insulator transition in the half-filled Hubbard model on a triangular lattice, with the interaction strength (U/t) and temperature as control parameters. We compute spectral and transport properties and estimate the Mott transition to occur at the critical interaction strength Uc/t=8.5+/-0.5. From the metallic side, the van Hove singularity in the density of states moves towards the Fermi level with increasing U/t and eventually collapses at the Mott transition, above which the Mott gap opens. In the quantum critical region above the transition point, the system exhibits a marginal Fermi liquid behavior. Due to the competition between electronic correlations and geometric frustrations, we observe non-trivial transport properties across the transition such as a universal jump in the resistivity, consistent with recent quantum field theory proposals. Implications for experiments on the layered triangular lattice organic material k-(BEDT-TTF)2Cu2(CN)3 and EtMe3Sb[Pd(dmit)2]2 are also discussed.