Heavy fermion fluid in high magnetic fields: an infrared study of CeRu$_4$Sb$_{12}$

TL;DR

This study uses infrared magneto-spectroscopy to investigate how high magnetic fields influence heavy quasiparticles in CeRu$_4$Sb$_{12}$, revealing a significant suppression of effective mass consistent with theoretical models.

Contribution

It provides the first detailed infrared analysis of magnetic field effects on heavy fermion quasiparticles in CeRu$_4$Sb$_{12}$, confirming theoretical predictions.

Findings

Effective mass m* is approximately 70 m_b at 10 K.

Magnetic field suppresses m* by up to 25% at 17 T.

Results agree with periodic Anderson model with Zeeman term.

Abstract

We report a comprehensive infrared magneto-spectroscopy study of CeRu$_4$Sb$_{12}$ compound revealing quasiparticles with heavy effective mass m$^*$, with a detailed analysis of optical constants in fields up to 17 T. We find that the applied magnetic field strongly affects the low energy excitations in the system. In particular, the magnitude of m$^*$ $\simeq$ 70 m$_b$ (m$_b$ is the quasiparticle band mass) at 10 K is suppressed by as much as 25 % at 17 T. This effect is in quantitative agreement with the mean-field solution of the periodic Anderson model augmented with a Zeeman term.