Doping-induced states near the Mott transition in the presence of antiferromagnetic order

Masanori Kohno

doi:10.1063/1.5042819

Abstract

A central issue of the Mott transition is how electronic states change in the Mott transition. Here, by taking into account spin fluctuation around the mean-field state using the random-phase approximation, electronic states exhibiting the spin-wave dispersion relation shifted by the Fermi momenta are shown to emerge in the Mott gap on doping an antiferromagnetically ordered Mott insulator. This characteristic contrasts with that of the mean-field approximation where doping does not induce electronic states in the gap. The results imply that this characteristic is general and fundamental to the Mott transition even in the presence of antiferromagnetic order.

Highlights

In the Mott transition, electronic states change from a Mott insulating state to a metallic state
A clear answer to this issue has recently been proposed: the low-energy spin excited states of a Mott insulator emerge as electronic states exhibiting the momentum-shifted magnetic dispersion relation in a doped Mott insulator, which lead to free-electron-like electronic states in the large-doping regime.[1,2,3,4,5,6,7]
Mean-field approximation In the mean-field approximation (MFA) for antiferromagnetic order,[8,9,10] the interaction term is approximated as HMU FA = −Um ξσck†+Q,σck,σ, (8)

Summary

Introduction

In the Mott transition, electronic states change from a Mott insulating state to a metallic state. It is widely believed that the electronic band structure of a Mott insulator remains essentially unchanged after doping as long as the antiferromagnetic order persists; holes would be injected around the top of the lower band and would behave as carriers as in the case of a doped band insulator. This conventional picture does not predict emergence of electronic states reflecting the low-energy spin excitation of the Mott insulator

Methods

Results

Conclusion