First-principles calculation of structural, electronic, and superconducting properties of PuH_x, 6 ≤ x ≤ 10

Plutonium polyhydrides are fascinating systems not only because plutonium is an important element in nuclear industry with complicated 5f electron behaviors, but also because metal polyhydrides are potential superconducting materials. Here, we have performed first-principles calculations, which adopts the projected-augmented wave (PAW) approach with the Perdew–Burke–Ernzerhof (PBE)-type functional including an on-site Hubbard U correction, to investigate the structural, electronic, and superconducting properties of hydrogen-rich PuH_x (6 ≤ x ≤ 10) in clathrate structure under high pressures up to 350 GPa. All systems are found to be metallic with occupied states near the Fermi level contributed mainly by Pu-5f electrons. The highest superconducting transition temperature T_c of PuH_x is only 26.4 K (PuH₁₀ under 300 GPa), and other predicted T_c are less than 1 K, showing that the f electrons in plutonium are harmful to the superconductivity in plutonium polyhydrides.