Revealing correlation effect of Co 3d electrons in La$_3$Co$_4$Sn$_{13}$ and Ce$_3$Co$_4$Sn$_{13}$ by infrared spectroscopy study

TL;DR

This study uses resistivity, specific heat, and optical spectroscopy to reveal the correlation effects of Co 3d electrons in La$_3$Co$_4$Sn$_{13}$ and Ce$_3$Co$_4$Sn$_{13}$, showing temperature-induced spectral weight suppression.

Contribution

It provides direct optical evidence of correlation effects of Co 3d electrons in these compounds, highlighting the formation of gap-like features with decreasing temperature.

Findings

Spectral weight suppression below 4000 cm$^{-1}$ with decreasing temperature.

Spectral weight transfer to higher energy regions.

Correlation effects attributed to Co 3d electrons.

Abstract

We report resistivity, specific heat and optical spectroscopy measurements on single crystal samples of La$_3$Co$_4$Sn$_{13}$ and Ce$_3$Co$_4$Sn$_{13}$. We observed clear temperature-induced spectral weight suppression below 4000 \cm for both compounds in conductivity spectra $\sigma_1(\omega)$, indicating the progressive formation of gap-like features with decreasing temperature. The suppressed spectral weight transfers mostly to the higher energy region. The observation reflects the presence of correlation effect in the compounds. We attribute the correlation effect to the Co 3d electrons.