First principles investigations of the electronic structure and chemical bonding of U3Si2C2 – A uranium silicide–carbide with the rare [SiC] unit

Abstract

The electronic structure of U3Si2C2, with the rare [SiC] unit is examined from ab initio with an assessment of the properties of chemical bonding. We show that plain GGA fails describing the experimental lattice parameters and the electronic structure. A better agreement with experiment (crystal determination and magnetic properties) is obtained with the GGA+U method and U=4eV. The energy–volume equation of state and the set of elastic constants are obtained showing incompressibility along the c-axis with U–C–Si alignment and a brittle material. Bonding of U1 and U2 selectively with Si and C and Si–C bonds are remarkable