Structural, electronic, mechanical and elastic properties of Scandium Chalcogenides by first-principles calculations

The Full-Potential Linearized-Augmented Plane Wave with Local Orbitals method (FPLAPW + LO) and the generalised gradient approximation (GGA) exchange-correlation potential are used to study the structural, electronic, elastic and mechanical properties of five different structures of ScX [X = S, Se]. The electronic properties are calculated using the modified Becke-Johnson (mBJ) approach. The elastic constants are calculated using the total energy approach with the package developed by Morteza Jamal. This is the first study of the properties of hexagonal structures of ScS and ScSe and awaits experimental results. Our results show that the NiAs phase of ScSe is stable and has a lower minimum energy than the rock-salt (RS) phase. Our calculated lattice parameters are in agreement with the literature and the electronic calculations show that ScS and ScSe are metallic in all five of the studied phases.