First-principles calculations of the ground-state properties and stability of ScN

Using first-principles total-energy calculations, we have studied the structural and electronic properties of ScN in the rocksalt (sodium chloride), cesium chloride, nickel arsenide, zinc-blende, and wurtzite structures. Rocksalt is the calculated ground-state structure with $a=4.54\mathrm{}\mathrm{\AA },$ $B_0=201\mathrm{}\mathrm{GPa}.$ Experimental values are $a=4.501\mathrm{}\mathrm{\AA },$ $B_0=182\mathrm{}\pm 40\mathrm{GPa}.$ There is an additional local minimum in the wurtzite structure. Its total energy is 0.34 eV/(unit formula) higher than the energy of the rocksalt structure. Since other group IIIA nitrides crystallize in the wurtzite structure, this result is important in the possible fabrication of Sc-IIIA-N alloys. At very high pressure, our calculations show the possibility of a phase transition from the NaCl to a metallic CsCl structure.