Spectral properties of delta-plutonium: Sensitivity to 5f occupancy

By combining the local density approximation (LDA) with dynamical mean field theory (DMFT), we report a systematic analysis of the spectral properties of delta-plutonium with varying 5f occupancy. The LDA Hamiltonian is extracted from a tight-binding fit to full-potential linearized augmented plane-wave calculations. The DMFT equations are solved by the exact quantum Monte Carlo (QMC) method and by the Hubbard-I approximation. We demonstrate strong sensitivity of the spectral properties to the 5f occupancy, which suggests using this occupancy as a fitting parameter in addition to the Hubbard U. By comparing with photoemission data, we conclude that the open shell 5f(5) configuration gives the best agreement, resolving the controversy over 5f open shell versus close shell atomic configurations in delta-Pu.