Protracted Kondo coherence with dilute carrier density in Cerium based nickel pnictides

TL;DR

This study investigates the protracted Kondo screening in cerium-based nickel pnictides with low carrier density, revealing strong three-dimensional electronic structures, Kondo resonance peaks, and quantum phase transitions driven by chemical pressure.

Contribution

It combines density functional theory and dynamical mean-field theory to analyze electronic structures and Kondo phenomena in cerium nickel pnictides, providing new insights into their quantum phase behavior.

Findings

Strong three-dimensional electronic structures with low Ni-3d contribution.

Presence of Kondo resonance peaks at low temperatures.

Quantum phase transition driven by As to P substitution.

Abstract

Nozi$\grave{e}$res' exhaustion theory argues the temperature for coherently screening of all local moments in Kondo lattice could be much lower than the temperature of single moment screening with insufficient number of conduction electrons. Recent experiment [Luo et al, PNAS, 112,13520 (2015)] indicates the cerium based nickel pnictides $CeNi_{2-\delta}As_2 (\delta\approx0.28)$ with low carrier density is an ideal material to exam such protracted Kondo screening. Using the density functional theory and dynamical mean-field theory, we calculated the respective electronic structures of paramagnetic $CeNi_2As_2$/$CeNi_2P_2$. In contrast to structurally analogous layered iron pnictides, the electronic structures of the present systems show strong three-dimensionality with substantially small contributions of Ni-3d electrons to the carrier density. Moreover, we find significant Kondo resonance peaks in the compressed $CeNi_2As_2$ and $CeNi_2P_2$ at low temperatures, accompanied by topological changes of the Fermi surfaces. We also find similar quantum phase transition in $CeNi_2As_2$ driven by chemical pressure via the isovalence As$\rightarrow$P substitution.