Reexaming the ground state and magnetic properties of curium dioxide

Abstract

The ground state electronic structure and magnetic behaviors of curium dioxide (CmO${}_2$) are controversial. In general, the formal valence of Cm ions in CmO${}_2$ should be tetravalent. It implies a $5f^{6.0}$ electronic configuration and a non-magnetic ground state. However, it is in sharp contrast with the large magnetic moment measured by painstaking experiments. In order to clarify this contradiction, we tried to study the ground state electronic structure of CmO${}_2$ by means of a combination of density functional theory and dynamical mean-field theory. We find that CmO${}_2$ is a wide-gap charge transfer insulator with strong 5$f$ valence state fluctuation. It belongs to a mixed-valence compound indeed. The predominant electronic configurations for Cm ions are $5f^{6.0}$ and $5f^{7.0}$. The resulting magnetic moment agrees quite well with the experimental value. Therefore, the magnetic puzzle in CmO${}_2$ can be appropriately explained by the mixed-valence scenario.

arXiv comment9 pages, 6 figures

References in corpus (22)

• Electronic Structure Calculations with Dynamical Mean-Field Theory: A Spectral Density Functional Approach
• Continuous-time Monte Carlo methods for quantum impurity models
• A continuous-time solver for quantum impurity models
• Quantum Monte Carlo Impurity Solver for Cluster DMFT and Electronic Structure Calculations in Adjustable Base
• Dynamical Mean-Field Theory within the Full-Potential Methods: Electronic structure of Ce-115 materials
• Nature of the 5f states in actinide metals
• Janus-faced influence of the Hund's rule coupling in strongly correlated materials
• What is the valence of a correlated solid? The double life of delta-plutonium
• Spin freezing transition and non-Fermi-liquid self-energy in a 3-orbital model
• Magnetic Moment Collapse-Driven Mott Transition in MnO
• Absence of magnetic moments in plutonium
• Electronic structure and ionicity of actinide oxides from first principles calculations
• The Valence-Fluctuating Ground State of Plutonium
• Many-Body Electronic Structure of Americium metal
• Microscopic theory of the insulating electronic ground states of actinide dioxides AnO2 (An=U, Np, Pu, Am, and Cm)
• Valence Fluctuations and Quasiparticle Multiplets in Pu Chalcogenides and Pnictides
• Electronic structure of cerium: A comprehensive first-principles study
• Pressure-driven 4$f$ localized-itinerant crossover in heavy fermion compound CeIn${}_3$: A first-principles many-body perspective
• Pressure-Driven 5$f$ Localized-Itinerant Transition and Valence Fluctuation in Californium
• Magnetic polarization of the americium $J=0$ ground state in AmFe${}_2$
• Itinerant-localized crossover and orbital dependent correlations for 4$f$ electrons in cerium-based ternary 122 compounds
• Magnetic behavior of curium dioxide with non-magnetic ground state