First-principles study of two-dimensional electride: Yttrium carbide

Electrides are an exclusive class of ionic compounds in which electrons serve as anions. We have performed first-principles density functional theory (DFT) calculations to investigate the structural, electronic and magnetic properties of two-dimensional layered-structure yttrium carbide (Y$_{2}$C). Generalized gradient approximation (GGA) with Projector Augmented Potentials (PAW) was used to obtain optimized lattice parameters, energy band structure, charge density and density of states (DOS) plots for Y$_{2}$C. The theoretically predicted structure of Y$_{2}$C is in good agreement with the experimental results. The band crossing the Fermi energy level proved that Y$_{2}$C has metallic properties. Additionally projected electronic density of states profiles were obtained to identify the electronic contribution from Y, C and non-atomic orbital located in interstitial site. The results of these calculations indicate that the presence of trapped electrons within the Y$_{2}$C interlayers. Furthermore, surface energies of Y-Y and Y-C were calculated and charge densities were plotted with these surfaces. Magnetization density plots were used to obtain magnetic properties.