Microscopic analysis of multipole susceptibility of actinide dioxides: A scenario of multipole ordering in AmO${}_2$

Abstract

By evaluating multipole susceptibility of a seven-orbital impurity Anderson model with the use of a numerical renormalization group method, we discuss possible multipole states of actinide dioxides at low temperatures. In particular, here we point out a possible scenario for multipole ordering in americium dioxide. For Am${}^{4+}$ ion with five $5f$ electrons, it is considered that the ground state is ${\Gamma }_7^{-}$ doublet and the first excited state is ${\Gamma }_8^{-}$ quartet, but we remark that the $f^5$ ground state is easily converted due to the competition between spin-orbit coupling and Coulomb interactions. Then, we find that the ${\Gamma }_8^{-}$ quartet can be the ground state of AmO${}_2$ even for the same crystalline electric field potential. In the case of ${\Gamma }_8^{-}$ quartet ground state, the numerical results suggest that high-order multipoles such as quadrupole and octupole can be relevant to AmO${}_2$.

8 pages, 4 figures. To appear in Phys. Rev. B

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Cited by in corpus (6)

• First-principles theory of magnetic multipoles in condensed matter systems
• Microscopic theory of the insulating electronic ground states of actinide dioxides AnO2 (An=U, Np, Pu, Am, and Cm)
• Effect of Spin-Orbit Coupling on Kondo Phenomena in $f^7$-Electron Systems
• Magnetic behavior of curium dioxide with non-magnetic ground state
• Two-Channel Kondo Effect Emerging from Np and Pu Ions
• Quadrupole Susceptibility of Gd-Based Filled Skutterudite Compounds