Development of empirical interatomic potential for Tin

Abstract

We have developed the empirical interatomic potential for Sn in terms of the Tersoff potential. Using a simulated annealing technique, we generate our potential by fitting it into the first-principles LDA calculations for the α-Sn and β-Sn phases of Sn. The resulting potential has been tested for various physical properties. The bulk modulus and phonon frequencies for the β-Sn phase are somewhat higher than the LDA calculations and experimental data. The lattice constant and bulk modulus of the α-Sn phase, the lattice constant of the β-Sn phase, and the cohesive energy difference between the two phases are in good agreement with the LDA calculations. We find that the elastic constants, and phonon dispersions for the α-Sn are described pretty well by our potential. Rescaling the phonon frequencies for the β-Sn, the P-T diagram of the two phases is in good agreement with the experimental results.