Influence of Magnetism and Correlation on the Spectral Properties of Doped Mott Insulators

TL;DR

This paper investigates how magnetism and electron correlations influence the spectral evolution of doped Mott insulators, revealing the interplay between coherence, correlation effects, and spin interactions during the insulator-metal transition.

Contribution

It demonstrates how electron-electron correlation and spin exchange interactions shape the spectral properties in doped Mott insulators, using cluster perturbation theory on Hubbard and t-J models.

Findings

Development of a quasi-free dispersion crossing the Fermi level with doping

Correlation effects destroy spectral coherence

Spin exchange interactions restore coherence in spectra

Abstract

Unravelling the nature of doping-induced transition between a Mott insulator and a weakly correlated metal is crucial to understanding novel emergent phases in strongly correlated materials. For this purpose, we study the evolution of spectral properties upon doping Mott insulating states, by utilizing the cluster perturbation theory on the Hubbard and t-J-like models. Specifically, a quasi-free dispersion crossing the Fermi level develops with small doping, and it eventually evolves into the most dominant feature at high doping levels. Although this dispersion is related to the free electron hopping, our study shows that this spectral feature is in fact influenced inherently by both electron-electron correlation and spin exchange interaction: the correlation destroys coherence, while the coupling between spin and mobile charge restores it in the photoemission spectrum. Due to the persistent impact of correlations and spin physics, the onset of gaps or the high-energy anomaly in the spectral functions can be expected in doped Mott insulators.