A Theoretical Investigation of the Metastability of Epitaxial α-Sn on a (100) Zinc Blende Substrate

The metastability of α-Sn with a diamond structure on a (100) zinc blende substrate is discussed based on cohesive energy calculations for bulk form and thin layers using the pseudopotential perturbation approach and universal empirical potentials. In the bulk form, α-Sn is found to be more stable than β-Sn with double-bct structure by 50 meV/atom at 0 K. However, the β-Sn is stabilized by the contribution of vibration entropy at high temperatures. The stabilization of α-Sn on the (100) zinc blende substrate is due to small coordination number change at the interface between thin films and substrate. On the zinc blende CdTe substrate, α-Sn is more stable than β-Sn by 291 meV/atom at the interface region and 628 meV/atom at the thin films region.