Unveiling the hybridization gap in Ce2RhIn8 heavy fermion compound

TL;DR

This study reveals the hybridization gap in Ce2RhIn8 heavy fermion compound using ARPES, showing its temperature dependence and how doping with Cd suppresses it, advancing understanding of Kondo lattice behavior.

Contribution

The paper provides direct spectroscopic evidence of the hybridization gap in Ce2RhIn8 and explores its temperature evolution and suppression through doping, which was not previously demonstrated.

Findings

Hybridization gap appears at lower temperatures than magnetic scattering.

The spectral gap is observed at higher temperature scales than the coherent temperature.

Cd doping reduces hybridization strength and suppresses the gap.

Abstract

A Kondo lattice of strongly interacting f-electrons immersed in a sea of conduction electrons remains one of the unsolved problems in condensed matter physics. The problem concerns localized f-electrons at high temperatures which evolve into hybridized heavy quasi-particles at low temperatures, resulting in the appearance of a hybridization gap. Here, we unveil the presence of hybridization gap in Ce2RhIn8 and find the surprising result that the temperature range at which this gap becomes visible by angle-resolved photoemission spectroscopy is nearly an order of magnitude lower than the temperature range where the magnetic scattering becomes larger than the phonon scattering, as observed in the electrical resistivity measurements. Furthermore the spectral gap appears at temperature scales nearly an order of magnitude higher than the coherent temperature. We further show that when replacing In by Cd to tune the local density of states at the Ce3+ site, there is a strong reduction of the hybridization strength, which in turn leads to the suppression of the hybridization gap at low temperatures.