Continuous Mott Transition and its Consequences on Transport Responses : A Cluster-DMFT Viewpoint

Motivated by theoretical suggestions of Mott quantum criticality in Hubbard-type models, we consider and perform an exact-to order-1/D (D = spatial dimensionality) calculation for the simplified Hubbard, or Falicov-Kimball model (FKM).  This is one of the rare examples of a lattice model exhibiting a continuous Mott transition, and we investigate the effects of inter-site spatial correlations upon this transition in an exactly solvable cluster theory.  We show that Landau quasiparticles are extinguished by a many-body orthogonality catastrophe.  The resulting transition turns out to be a momentum-selective one, a specific semi-analytic demonstration of such  a feature in a concrete lattice model.

We also discuss transport responses in detail.  In particular, we will show resistivity, Seebeck co-efft, thermal conductivity and Hall effect and discuss how these evolve in a very nomalous way close to the Mott transition.  Breakdown of the Landau picture will be shown to have very drastic consequences for transport in the critical regime, which will be emphasized.  Finally, the close similarity of our results with experimental data from the IISc group of A. Ghosh et al will be pointed out.