The aim of the present work, based on ab-initio calculations, is to investigate the relative stabilities of the different compounds involved in the (Pt-Sn) system. Having   our calculations performed at 0K, We will be mainly focusing on the determination of the ground state line of this system.

Our calculations were based on density functional theory (DFT) as implanted in the Vasp

Code [1] .We   used the projector augmented-wave (PAW) method, which is an all-electrons technique within the frozen core approximation .Only   generalized-gradient approximation (GGA) was considered.  A study of convergence has been done for the plane-wave cutoff energy and allowed us to fix the Ecut at     520eV     .The formation enthalpies of the compounds were obtained   through the following equation:

H_f (Pt_p Snq)=E_tot (Pt_p Snq)- (E^fcc E^BCT ,

Where  H_f(Pt_p Sn_q)  is  the  enthalpy of formation of the compound  Pt_p Sn_q ,     E_tot(Pt_p Sn_q),      E^fcc(Pt) and E^BCT (Sn) are the ground  state total energies  (per atom) of the compound  Pt_p Sn_q and its  constituents  Pt and Sn,  respectively, in fcc and BCT structure.

References

[1] : G. Kresse and J. Furthmuller, Efficiency of Ab-Initio Total Energy Calculations for Metals and Semiconductors Using a Plane-Wave Basis Set, Comput. Mater. Sci., 1996, 6, p 15-50.