Crystal field excitations of heavy fermion antiferromagnetic superconductor using inelastic neutron scattering

Rare earth intermetallic compounds exhibit fascinating phenomena, such as heavy fermion behaviour and superconductivity, owing to the interplay of interactions like RKKY exchange, spin-orbit coupling, and the crystal electric field (CEF). Specifically, Ce2RhIn8 displays pressure-induced superconductivity and acts as a three-dimensional counterpart to the well-studied CeRhIn5. The CEF splitting of Ce energy levels is a pivotal parameter for tuning the electronic properties of these materials, and previous studies indicate that Ce2RhIn8 has two low-lying CEF states that significantly influence its ground-state physics. However, the proposed CEF schemes from these studies are inconsistent as they were derived indirectly from the data. We propose a direct measurement of the CEF scheme in Ce2RhIn8 using inelastic neutron scattering, which will allow us to examine transitions between the CEF states and obtain precise values for energy levels, wave functions, and transition strengths. To this end, we will utilize the MERLIN instrument, which offers high flux at Ei = 50 meV and can operate in repetition-rate multiplication mode. This enables simultaneous data collection at Ei = 50 meV, 21.76 meV, and 12.12 meV (using a Gd chopper at 300 Hz), covering the relevant energy region. Data collected at 5 K and 180 K will be analyzed simultaneously to extract the necessary CEF parameters.