Fermionic Critical Fluctuations: Potential Driver of Strange Metallicity and Violation of the Wiedemann-Franz Law in YbRh2Si2

TL;DR

This study investigates how fermionic quantum critical fluctuations near a Kondo-destroying quantum critical point in YbRh2Si2 cause strange-metal behavior and violate the Wiedemann-Franz law, revealing new inelastic scattering mechanisms.

Contribution

It identifies fermionic quantum critical fluctuations as the primary cause of strange-metal behavior and Wiedemann-Franz law violation in YbRh2Si2, linking Fermi-surface fluctuations to transport anomalies.

Findings

Detection of a new inelastic scattering center for charge and heat carriers.

Fermi-surface fluctuations are linked to strange-metal behavior.

Fermionic quantum critical fluctuations drive the Wiedemann-Franz law violation.

Abstract

Results of combined thermal and electrical transport measurements through the magnetic field-induced quantum critical point in the heavy-fermion compound YbRh2Si2 are revisited to explore the relationship between the strange-metal behavior, observed in both the electrical and electronic thermal resistivity, and the violation of the Wiedemann-Franz law in the zero-temperature limit. A new type of inelastic scattering center for the charge and heat carriers has been detected and ascribed to the small-to-large Fermi-surface fluctuations. These are operating in the vicinity of and at the Kondo-destroying quantum critical point as fermionic quantum critical fluctuations and are considered the primary driver of the strange-metal behavior and the violation of the Wiedemann-Franz law.