Magnetic Field Driven Electronic Singularities through Metamagnetic Phenomena: Case of the Heavy Fermion Antiferromagnet Ce(Ru0.92Rh0.08)2Si2

TL;DR

This study investigates how magnetic fields induce electronic singularities in a heavy fermion antiferromagnet, revealing decoupled magnetic and electronic transitions and their relation to Fermi surface topology changes.

Contribution

It demonstrates the decoupling of antiferromagnetic order from metamagnetic crossover and identifies electronic singularities associated with magnetic instabilities in Ce(Ru0.92Rh0.08)2Si2.

Findings

Antiferromagnetic state is fully decoupled from the pseudo-metamagnetic crossover.

Two electronic singularities with opposite signs are observed in thermoelectric power.

Magnetic instability is linked to topological changes in the Fermi surface.

Abstract

Thermoelectric power measurements on the heavy fermion antiferromagnet Ce(Ru0.92Rh0.08)2Si2 under magnetic field (H) show clearly that the antiferromagnetic state below the critical field Hc ~ 2.8T can be fully decoupled from the pseudo-metamagnetic crossover at Hm ~ 5.8T which occurs when the magnetization reaches a critical value. By contrast to the weak field variation of the Sommerfeld coefficient of the specific heat in the field window from Hc to Hm, two electronic singularities with opposite signs are detected in the thermoelectric power. The interplay between the magnetic instability and the topological change of the Fermi surface is discussed and we argue similarities to other field instabilities in various heavy fermion compounds.