Doping-driven Mott transition in the one-band Hubbard model

TL;DR

This paper uses a new impurity solver within dynamical mean field theory to study the doping-driven Mott transition in the one-band Hubbard model, revealing a second-order transition with reduced compressibility and in-gap states at low doping.

Contribution

It introduces a powerful impurity solver enabling detailed analysis of the doping-driven Mott transition at zero temperature in the Hubbard model.

Findings

The transition is second order at T=0.

Electronic compressibility vanishes at the critical interaction.

In-gap states appear only at very low dopings (<3%).

Abstract

A powerful new impurity solver is shown to permit a systematic study of the doping driven Mott transition in a one-band Hubbard model within the framework of single-site dynamical mean field theory. At small dopings and large interaction strengths we are able access low enough temperatures that a reliable extrapolation to temperature T=0 may be performed, and ground state energies of insulating and metallic states may be compared. We find that the T=0 doping-driven transition is of second order and is characterized by an interaction-strength dependent electronic compressibility, which vanishes at the critical interaction strength of the half filled model. Over wide parameter ranges the compressibility is substantially reduced relative to the non-interacting system. The metal insulator transition is characterized by the appearance of in-gap states, but these are relevant only for very low dopings of less than 3%.