Pseudogap and Mott Transition Studied by Cellular Dynamical Mean Field Theory

TL;DR

This paper investigates the metal-insulator transition in correlated electron systems using a cluster extension of dynamical mean field theory, revealing a different transition mechanism involving a sudden gap opening and momentum space differentiation.

Contribution

It introduces a cluster extension of DMFT that captures a distinct transition mechanism, contrasting with the original DMFT, and explains experimental observations in certain transition metal oxides.

Findings

Quasiparticle weight remains nonzero until the transition

Gap opens continuously in insulators

Results align with experiments on CaVO3 and SrVO3

Abstract

We study metal-insulator transitions between Mott insulators and metals. The transition mechanism completely different from the original dynamical mean field theory (DMFT) emerges from a cluster extension of it. A consistent picture suggests that the quasiparticle weight $Z$ remains nonzero through metals and suddenly jumps to zero at the transition, while the gap opens continuously in the insulators. This is in contrast with the original DMFT, where $Z$ continuously vanishes but the gap opens discontinuously. The present results arising from electron differentiation in momentum space agree with recent puzzling bulk-sensitive experiments on CaVO$_3$ and SrVO$_3$.