Temperature dependent tunneling spectroscopy in the heavy fermion CeRu2Si2 and in the antiferromagnet CeRh2Si2

TL;DR

This study uses temperature-dependent tunneling spectroscopy to compare the electronic states of two heavy fermion compounds, CeRu2Si2 and CeRh2Si2, revealing how their conductance features evolve across magnetic and coherence transitions.

Contribution

It provides the first detailed tunneling spectroscopy analysis of these compounds across a range of temperatures, highlighting differences related to their magnetic states.

Findings

V-shaped dips in conductance at 0.15 K in both compounds

Disappearance of dips above coherence and Néel temperatures

Identification of two types of V-shaped conductance dips in CeRh2Si2

Abstract

CeRu2Si2 and CeRh2Si2 are two similar heavy fermion stoichiometric compounds located on the two sides of the magnetic quantum critical phase transition. CeRh2Si2 is an antiferromagnet below T_N=36 K with moderate electronic masses whereas CeRu2Si2 is a paramagnetic metal with particularly heavy electrons. Here we present tunneling spectroscopy measurements as a function of temperature (from 0.15 K to 45 K). The tunneling conductance at 0.15 K reveals V-shaped dips around the Fermi level in both compounds, which disappear in CeRu2Si2 above the coherence temperature, and above the N\'eel temperature in CeRh2Si2. In the latter case, two different kinds of V-shaped tunneling conductance dips are found.