A new empirical interatomic potential for compound semiconductors and its application to thermodynamic stabilities

We proposed a new empirical interatomic potential for compound semiconductors applicable to estimation of subtle energy difference. The potential was devised to incorporate the interactions between atoms beyond 3rd neighbors by considering electrostatic contributions. The versatility of the potential was confirmed by the calculation of relative stabilities between wurtzite and zinc blende structures. Using the new potential, we also worked out the excess energies for In/sub x/Ga/sub 1-x/N/GaN and In/sub x/Ga/sub 1-x/N/InN in order to investigate thermodynamic stabilities. We found that the excess energy maximum drastically shifted toward x/spl sim/0.80 for InGaN/GaN and x/spl sim/0.10 for InGaN/InN due to the lattice constraint from the bottom layer in contrast with x/spl sim/0.50 for bulk.