Exchange-renormalized crystal field excitations in the quantum Ising magnet KTmSe2

Emerging as a platform for novel quantum effects, triangular-lattice rare-earth delafossite compounds have attracted significant attention. This study investigates KTmSe${}_{2}$ using thermodynamic and neutron scattering methods, revealing highly dispersive crystal electric field excitations. From the transverse field Ising model and a full crystal field scheme, the findings uncover a strong interplay between spin exchange interactions and crystal field effects. These insights will provide a valuable framework for understanding low-temperature magnetism in materials of a similar type.