Magnetic excitation emergence relevant to carrier scattering in semimetal Yb$_3$Ir$_4$Ge$_{13}$

TL;DR

This study uses inelastic neutron scattering to reveal low-energy magnetic excitations in Yb$_3$Ir$_4$Ge$_{13}$, linking magnetic fluctuations to anomalous electrical resistivity in this semimetal.

Contribution

It provides the first observation of magnetic excitations in Yb$_3$Ir$_4$Ge$_{13}$ and connects these to carrier scattering and resistivity anomalies.

Findings

Magnetic excitation appears below 3 meV with short spatial correlation.

No crystal-field-split levels observed up to 60 meV.

Magnetic fluctuations are linked to resistivity enhancement below 20 K.

Abstract

Inelastic neutron scattering experiments have been conducted to investigate the semimetal system Yb$_3$Ir$_4$Ge$_{13}$. No clear crystal-field-split levels were observed up to an excitation energy of 60 meV, while a magnetic excitation appears at low energy below approximately 3 meV. This excitation shows a short spatial correlation, and an energy spectrum is reproduced by an imaginary part of generalized magnetic susceptibility on the basis of a damped harmonic oscillator model. The magnetic excitation emerges simultaneously with an anomalous electrical-resistivity enhancement below 20 K. The close relationship between the magnetic and transport behaviors evidences that the semimetal carriers are scattered by magnetic fluctuation dominated by the Yb $4f$ state.