First-principles elastic constants and phonons of $\delta \text{‐}\mathrm{Pu}$

Elastic constants and zone-boundary phonons of $\delta$-plutonium have been calculated within the density-functional theory. The paramagnetic state of $\delta \text{‐}\mathrm{Pu}$ is modeled by disordered magnetism utilizing either the disordered local moment or the special quasirandom structure techniques. The anomalously soft $C^{\prime }$ as well as a large anisotropy ratio $(C_{44}∕C^{\prime })$ of $\delta \text{‐}\mathrm{Pu}$ is reproduced by this theoretical model. Also the recently measured phonons for $\delta \text{‐}\mathrm{Pu}$ compare relatively well with their theoretical counterpart at the zone boundaries.