Structural phase transition and 5f-electrons localization of PuSe explored by ab initio calculations

An investigation into the structural phase transformation, electronic and optical properties of PuSe under high pressure was conducted by using the full potential linearized augmented plane wave plus local orbitals (FP-LAPW+lo) method, in the presence and in the absence of spin–orbit coupling (SOC). Our results demonstrate that there exists a structural phase transition from rocksalt (B 1) structure to CsCl-type (B 2) structure at the transition pressure of 36.3 GPa (without SOC) and 51.3 GPa (with SOC). The electronic density of states (DOS) for PuSe show that the f -electrons of Pu are more localized and concentrated in a narrow peak near the Fermi level, which is consistent with the experimental studies. The band structure shows that B 1-PuSe is metallic. A pseudogap appears around the Fermi level of the total density of states of B 1 phase PuSe, which may contribute to its stability. The calculated reflectivity R(ω)R(ω) shows agreement with the available experimental results. Furthermore, the absorption spectrum, refractive index, extinction coefficient, energy-loss spectrum and dielectric function were calculated. The origin of the spectral peaks was interpreted based on the electronic structures.