Theoretical studies of cubic AuCu3-type intermetallic actinide compounds NpPx3 (Px=Al, Ga, In)

In this paper, we explore the structural, magnetic, electronic specific heat, electric field gradient (EFG) as well as quadrupole coupling constant of NpPx3 (Px = Al, Ga, In) by using LDA, GGA, GGA + U and HF-PBEsol. The relativistic effects of electrons of the actinides are considered by spin-orbit coupling calculations. The comparison of the calculated structural parameters, magnetic moments and EFG of these materials satisfy the available experimental results. This consistency shows the effectiveness of our theoretical tools. The calculated EFG and quadrupole coupling constant value increase in NpPx3 from Al to In due to change of fermions. The EFG and quadrupole coupling constant in NpPx3 (Px = Al, Ga, In) is mainly originated from f-f and p-p contributions of Np atom and p-p contribution of Al, Ga and In atom.