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

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.

6 pages, 4 figures