Agradecimentos: All authors thank Manuel Brando, Otavio L. Canton, Miguel F. Carvalho, Eduardo Granado, and Daisuke Takegami for enlightening discussions. A.S. benefited from support of the German Research Foundation (DFG), Project No. 387555779. G.Z. acknowledges that this research was supported in part by Grant No. NSF PHY-2309135 to the Kavli Institute for Theoretical Physics (KITP). A.M.C., M.H.C., and P.G.P. benefited from support from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (São Paulo, Brazil; Grants No. 20/10580-8 and No. 22/16823-5), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (Brazil, Grants No. 405408/2023-4714 and No. 311783/2021-0), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (Brazil). Work at Los Alamos was performed under the auspices of the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. We acknowledge support from the Max Planck-POSTECH-Hsinchu Center for Complex Phase Materials Ver menos

Abstract: The higher dimensionality in the crystal fields of the Ce2MIn8 (M = Rh, Ir) compounds and its interplay with hybridization and disorder are key ingredients to understand the complex phase diagrams by this family, which have been explored extensively by macroscopic techniques. Here, we present an investigation of the crystalelectric field schemes of Ce2Rh1-xIrxIn8 using x-ray absorption spectroscopy. Our full multiplet calculations for the 4f(1) configuration of Ce3+ to describe the temperature-dependent linear dichroism in Ce2MIn8 are consistent with a Gamma(1)(7) = root/1 - alpha(2) center dot vertical bar -/+ 3/2 > - vertical bar center dot vertical bar +/- 5/2 > ground state containing a predominant d +/- 3/2) contribution that increases further with x. This enhancement is believed to favor superconductivity in Ce-based heavy fermion materials, observed in previous results in the CeMIn5 family. Our recent observations shed light on the unexpected emergence of the ambient-pressure superconducting dome in the center of the composition phase diagram and its subsequent suppression on the Ir-rich side due to the early onset of fluctuations associated with the structurally more disordered state, inferred from previous neutron magnetic diffraction experiments Ver menos