Tight-binding molecular dynamics study of hydrogen molecule inside silicon crystal

Tight-binding molecular dynamics simulations were carried out to investigate the dynamics of a H2 molecule within a silicon crystal using a cluster model. The global minimum of the H2 molecule's configuration was found to be at the tetrahedral interstitial site along the 〈100〉 direction. This is in good agreement with the results of first-principles quantum calculations. The H2 molecule was trapped at this site up to a temperature of 600 K. At 900 K, the H2 molecule diffused into the silicon crystal through the hexagonal site of the silicon lattice while retaining the H-H bond. These results justify the stability of the H2 molecule inside the silicon crystal and the possibility of diffusion of the H2 molecule in the silicon crystal without dissociation.