First-Principles Study of Structural, Magnetic, Electronic and Elastic Properties of PuC₂

We perform first-principles calculations of crystal structure, magnetism, electronic structure, chemical bonding and elastic properties for PuC₂ using the standard local spin-density approximation (LSDA)+U scheme. The use of the Hubbard term to describe the 5f electrons of plutonium is discussed according to the lattice parameters, magnetism and densities of states. Our calculated lattice constants and magnetism are in good agreement with the experimental data or other theoretical calculations. It is shown that the total densities of states at the Fermi energy level mainly come from the contribution of narrow f band. The Pu-C bonds of PuC₂ have a mixture of covalent character and ionic character, while covalent character is stronger than ionic character. The C1-C2 bonding has strong covalent character because of sp² hybridization between C atoms. Lastly, the elastic properties of PuC₂ are studied. We hope that our results can provide a useful reference for further theoretical and experimental research on PuC₂. (paper)