重费米子超导PuMGa₅ (M=Co,Rh)结构,电子和热力学性质的第一性原理研究

Crystal structure, elasticity, electronic properties, phonon spectra and thermodynamic properties of PuCoGa₅ and PuRhGa₅ were studied with first-principles PBEsol+U method. PBEsol+U method is used to account for strong on-site Coulomb repulsion among localized Pu 5f electrons. Our results shown that the ground state properties, including lattice parameters and atomic sites, are agree well with experimental data. Mechanical properties and phonon dispersion indicated that the ground state structures (at zero temperature and pressure conditions) of PuCoGa₅ and PuRhGa₅ are stable. In particular, 5f electrons of PuCoGa₅ and PuRhGa₅ have obvious localization near Fermi level, and the localization of 5f electrons of PuRhGa₅ is obviously stronger than that of PuCoGa₅, which may be the reason that the superconducting critical transition temperature T_c of PuCoGa₅ is higher than that of PuRhGa₅. In addition, thermodynamic properties of PuCoGa₅ and PuRhGa₅ include Helmholtz free energy, entropy, internal energy and isovolume molar heat capacity have similar dependence on temperature.