Temperature-driven emergence of local moment in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>δ</mml:mi> </mml:math> -plutonium

In this work, the electronic structure, the uniform magnetic susceptibility, and the static and dynamic local magnetic susceptibilities of $\ensuremath{\delta}$-Pu are investigated with the help of density functional theory (DFT) plus dynamical mean-field theory. Consistent with experimental observations and at variance with DFT, the ground state at low temperature is found to be nonmagnetic and characterized as a mixed-valence system, where the local magnetic moment from the partially filled $5f$ shell is effectively screened by the conduction electrons. Importantly, as the temperature rises a local magnetic moment emerges with antiparallel orbital and spin angular momenta, leading to a transition from a Pauli-like behavior to an apparent weak Curie-Weiss magnetism in the uniform magnetic susceptibility. The crossover regime corresponds to the emergence of a local moment as evidenced by the local susceptibilities. This finding reconciles previous discrepancies between experimental observation and theoretical simulations.