Two-channel Kondo effect emerging from Np and Pu ions

On the basis of an idea of the electron-hole relation between f² and f⁴ states in a j-j coupling scheme, we point out a possibility that two-channel Kondo phenomena can be observed even in cubic transuranium compounds including Np and Pu ions with local Γ₃ non-Kramers doublet ground state. For the purpose, we analyze a seven-orbital impurity Anderson model hybridized with degenerate Γ₈ conduction electron bands by employing a numerical renormalization group method. From the numerical results for the case of four local f electrons, corresponding to Np³⁺ and Pu⁴⁺ ions, we confirm that a residual entropy of 0.5 log 2, a characteristic of two-channel Kondo phenomena, appears for the case with the local Γ₃ doublet ground state. (author)