Two-Channel Kondo Effect Emerging from Np and Pu Ions

TL;DR

This paper proposes that two-channel Kondo effects can occur in cubic transuranium compounds with Np and Pu ions, based on electron-hole symmetry and numerical analysis of a seven-orbital impurity Anderson model.

Contribution

It introduces a new possibility of observing two-channel Kondo phenomena in Np and Pu compounds with specific ground states, supported by numerical renormalization group calculations.

Findings

Residual entropy of 0.5 log 2 observed, indicating two-channel Kondo effect.

Analysis confirms the emergence of two-channel Kondo phenomena in Np and Pu ions with $ ext{f}^4$ configuration.

Theoretical prediction based on electron-hole symmetry in a seven-orbital model.

Abstract

On the basis of an idea of the electron-hole relation between $f^2$ and $f^4$ 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 $\Gamma_3$ non-Kramers doublet ground state. For the purpose, we analyze a seven-orbital impurity Anderson model hybridized with degenerate $\Gamma_8$ conduction electron bands by employing a numerical renormalization group method. From the numerical results for the case of four local $f$ electrons, corresponding to Np$^{3+}$ and Pu$^{4+}$ 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 $\Gamma_3$ doublet ground state.