The dependence of the formation enthalpy (Hf) of the self-interstitial I and the vacancy V on the hydrostatic pressure P was obtained by calculating the formation energy (Ef) and the relaxation volume (vf). The dependence of the migration enthalpy (Hm) of I and V on the pressure P was also obtained by calculating the change of Hf during the migration. Density functional theory calculations were used with 216-atom super-cells and with special attention for the convergence of the calculations. The neutral I and V were found to have quasi-constant formation energies EfI and EfV for pressures of between -1 to +1GPa. For the relaxation volume, vfI was almost constant while vfV decreased with increasing pressure P. The formation and migration enthalpies HfI and HmI, respectively, at the [110] dumb-bell site were given by HfI(eV)  = 3.425 - 0.055P and HmI(eV)  = 0.981 - 0.039P with hydrostatic pressure P given in GPa. The HfV and HmV dependences upon P were given by HfV(eV)  =3.543 - 0.024P2- 0.009P and HmV (eV) = 0.249 + 0.005P2 - 0.030P. These results indicated that hydrostatic pressure led to a slight increase of the equilibrium concentration and diffusion of vacancies but this increase was considerably smaller than that of self-interstitials.

DFT Study of the Effect of Hydrostatic Pressure on Formation and Migration Enthalpies of Intrinsic Point Defects in Single Crystal Si. K.Sueoka, E.Kamiyama, H.Kariyazaki, J.Vanhellemont: Physica Status Solidi C, 2012, 9[10-11], 1947-51