Evolution of the Kondo resonance feature and its relationship to spin-orbit coupling across the quantum critical point in Ce2Rh{1-x}CoxSi3

TL;DR

This study examines how the electronic structure and Kondo resonance features evolve across a quantum critical point in Ce2Rh{1-x}CoxSi3, highlighting the role of spin-orbit coupling and hybridization effects.

Contribution

It provides new insights into the evolution of Kondo resonance and spin-orbit interactions across the quantum critical point in Ce-based compounds.

Findings

Kondo resonance features are present across all compositions.

The KRF/SOC intensity ratio increases with decreasing temperature in strong hybridization.

Finite Kondo temperature persists within the magnetically ordered phase.

Abstract

We investigate the evolution of the electronic structure of Ce2Rh{1-x}CoxSi3 as a function of x employing high resolution photoemission spectroscopy. Co substitution at the Rh sites in antiferromagnetic Ce2RhSi3 leads to a transition from an antiferromagnetic system to a Kondo system, Ce2CoSi3 via the Quantum Critical Point (QCP). High resolution photoemission spectra reveal distinct signature of the Kondo resonance feature (KRF) and its spin orbit split component (SOC) in the whole composition range indicating finite Kondo temperature scale at the quantum critical point. We observe that the intensity ratio of the Kondo resonance feature and its spin orbit split component, KRF/SOC gradually increases with the decrease in temperature in the strong hybridization limit. The scenario gets reversed if the Kondo temperature becomes lower than the magnetic ordering temperature. While finite Kondo temperature within the magnetically ordered phase indicates applicability of the spin density wave picture at the approach to QCP, the dominant temperature dependence of the spin-orbit coupled feature suggests importance of spin-orbit interactions in this regime.