Suppression of hybridization by Cd doping in CeCoIn 5

Abstract

The interaction between superconductivity and magnetism in heavy fermion compounds has remained a challenge ever since the discovery of unconventional superconductivity in such systems. The heavy fermion Ce T In 5 ( T = Co,Rh,Ir) family offers a good platform to study the relationship between superconductivity and magnetism, whose ground state can be easily tuned by chemical doping, making the ambient-pressure experimental techniques like angle-resolved photoemission spectroscopy possible to address this old but engaging question. By Cd doping, the superconducting state of CeCoIn 5 can be smoothly tuned to an antiferromagnetic ground state, which can be reversed by applying pressure. In this study, we present an electronic structure study of CeCo ( In 0.85 Cd 0.15 ) 5 with an antiferromagnetic ground state and the results are compared with CeCoIn 5 . We found that the hybridization strength between the f electrons and conduction electrons in CeCoIn 5 has been suppressed by Cd doping, but still the Fermi surface includes a significant contribution from the Ce f electrons. Our results find that the electronic tuning effect by Cd doping arises from the change in the hybridization strength between the Ce f electrons and conduction electrons caused by the Cd dopant, and the subtle interplay between itinerancy and localization of the f electrons determines the ground state.