Investigation of equation of states and electronic properties of Am and Cm metals in their gamma plutonium phase using GGA+SO+U method

•DFT failed to estimate EOS (mismatch>15%).•GGA+SO+U gave accurate EOS.•5f electrons remain localized.

Pressure–volume equation of state for Am and Cm metals were studied in their gamma plutonium phase using GGA+SO+U method. Non-magnetic density functional theory with GGA exchange-correlation failed to estimate structural parameters and equation of states accurately. As expected, inclusion of onsite Hubbard interaction (U) between 5f electrons shows enormous effect on electronic and bulk properties. Nonmagnetic GGA+SO+U (=4.0 eV for Am and 5.5 eV for Cm) calculated EOS gives very good match with that of experimental data. Equally good match of EOS was found for spin-polarized GGA+SO+U calculations with much smaller Hubbard parameter.