Cluster Dynamical Mean Field analysis of the Mott transition

TL;DR

This study uses cluster dynamical mean field theory to analyze the Mott transition, revealing the absence of a finite temperature transition without frustration and identifying momentum-dependent electron lifetimes with reduced effective mass near the transition.

Contribution

It introduces a cluster extension of DMFT to study the Mott transition, highlighting the role of frustration and momentum dependence in electron properties.

Findings

No finite temperature Mott transition without frustration.

Signatures of a finite temperature Mott critical point in frustrated models.

Momentum-dependent electron lifetime and reduced effective mass near the transition.

Abstract

We investigate the Mott transition using a cluster extension of dynamical mean field theory (DMFT). In the absence of frustration we find no evidence for a finite temperature Mott transition. Instead, in a frustrated model, we observe signatures of a finite temperature Mott critical point in agreement with experimental studies of kappa-organics and with single site DMFT. As the Mott transition is approached, a clear momentum dependence of the electron lifetime develops on the Fermi surface with the formation of cold regions along the diagonal direction of the Brillouin zone. Furthermore the variation of the effective mass is no longer equal to the inverse of the quasi particle residue, as in DMFT, and is reduced approaching the Mott transition.