Optical and magnetic excitations in the underscreened quasiquartet Kondo lattice

This paper investigates the non-conventional quasiparticle bands of the underscreened Kondo lattice with quasi-quartet crystalline electric field splitting and their signature in optical and magnetic dynamics. The authors show that a central heavy band inside the main hybridization gap leads to direct optical transitions already for frequencies corresponding to the low energy Kondo scale.