Evidence of charge‐density waves in the optical properties of SmNiC

Abstract

Abstract[94pt]In this study, we have measured the optical reflectivity spectra of low‐dimensional SmNiC ( K and K) in the terahertz to ultraviolet frequency range at various temperatures. The optical conductivity spectra were transformed from the reflectivity data using the Kramers–Kronig relation. The optical conductivity of the normal state is well described by the Drude–Lorentz model assuming two bands. In nonmagnetic states below , two clean gaps opening on top of the Drude response are observed at around 500 and 750 cm−1. In the ferromagnetic state, the higher‐side gap opening remains at the same frequency but the lower‐side gap opening disappears, instead an additional absorption due to magnon gap formation is observed at around 70 cm−1.