A path to poor coherence in heavy fermions from Mott physics and hybridization

TL;DR

This paper explores how hole doping in the periodic Anderson model leads to poor electronic coherence due to hybridization effects, resulting in Zhang-Rice-like singlets and deviations from Fermi-liquid behavior at low temperatures.

Contribution

It demonstrates the formation of composite quasi-particles and poor coherence in hole-doped Mott insulators, highlighting the role of hybridization and magnetic properties.

Findings

Exponential suppression of coherence temperature at low doping

Formation of Zhang-Rice-like singlets in hole-doped regime

Deviation from Fermi-liquid theory at small temperatures

Abstract

We investigate the anomalous metal arising by hole doping the Mott insulating state of the periodic Anderson model. Using Dynamical Mean-Field Theory we show that, as opposed to the electron-doped case, in the hole-doped regime the hybridization between localized and delocalized orbitals leads to the formation of composite quasi-particles reminiscent of the Zhang-Rice singlets. We compute the coherence temperature of this state, showing its exponentially small value at low dopings. As a consequence the weakly-doped Mott state deviates from the predictions of Fermi-liquid theory already at small temperatures. The onset of the Zhang-Rice state and of the consequent poor coherence is due to the electronic structure in which both localized and itinerant carriers have to be involved in the formation of the conduction states and to the proximity to the Mott state. By investigating the magnetic properties of this state, we discuss the relation between the anomalous metallic properties and the behavior of the magnetic degrees of freedom.