Recent Advances in Ce-Based Heavy-Fermion Superconductivity and Fermi Surface Properties

Abstract

We present the recent advances in Ce-based heavy fermion superconductivity. Heavy fermions are formed by the competition between the Ruderman–Kittel–Kasuya–Yosida interaction and the Kondo effect. The application of pressure is useful for controlling the electronic states in antiferromagnets such as CeRh₂Si₂, Ce₂Ni₃Ge₅, CeIn₃, CeRhIn₅, and CeIrSi₃. For these compounds, the Néel temperature T_N decreases with increasing pressure and reaches zero at the quantum critical pressure P_c. Superconductivity appears around P_c. In CeRu₂, CeCoIn₅, and CePt₃Si, superconductivity is realized at ambient pressure. For these pressure-induced and ambient-pressure superconductors, we clarified their unconventional characteristics of superconductivity, the close relationship between superconductivity and the dimensionality of the electronic states, and a new aspect of superconductivity in the non-centrosymmetric crystal structure, together with its Fermi surface instability at P_c.