Mott Transition and Strange Metal in Two Dimensional Hubbard Model. What can Cluster-DMFT tell us?

Mukul Laad


Max-Planck-Institut Dresden
Motivated by the unusual non-Fermi Liquid (nFL) responses observed around optimal doping in cuprates, we construct a new cluster-DMFT for the 2D extended Hubbard model on a square lattice. At half-filling, a d-wave Mott insulator is obtained for strong coupling (Uarrowinfty, V>>t). Hole doping drives a first order Mott transition to a d-wave pseudogapped (d-PG), incoherent metal. Remarkably, when the d-PG vanishes (``optimal'' doping), we recover a scale-invariant non-FL metallic state. In our C-DMFT, this arises due to an Anderson orthogonality catastrophe resulting from strong scattering between non-local (cluster) electronic channels with different ``orbital'' symmetries. This is the first demonstration of Anderson's ideas within C-DMFT schemes. We use these results to show how many unusual observations around optimal doping are understood naturally from our approach.
Reference: ``Mott Transition and Strange Metal in Two Dimensions. A View From Cellular DMFT.'', by M. S. Laad and L. Craco, cond-mat/0701585, submitted to Phys. Rev. Lett.