Optical study on electronic structure of the locally non-centrosymmetric CeRh$_2$As$_2$

Abstract

The electronic structures of the heavy-fermion superconductor CeRh2As2 with the local inversion symmetry breaking and the reference material LaRh2As2 have been investigated by using experimental optical conductivity (σ1(ω)) spectra and first-principal DFT calculations. In the low-temperature σ1(ω) spectra of CeRh2As2, a 4f -conduction electron hybridization and heavy quasiparticles are clearly indicated by a mid-infrared peak and a narrow Drude peak. In LaRh2As2, these features are absent in the σ1(ω) spectrum, however, it can nicely be reproduced by DFT calculations. For both compounds, the combination between a local inversion symmetry breaking and a large spin-orbit (SO) interaction plays an important role for the electronic structure, however, the SO splitting bands could not be resolved in the σ1(ω) spectra due to the small SO splitting size.