High pressure dependence of positron states in zinc-blende boron nitride

This paper reports on calculations of the positron annihilation characteristics under high hydrostatic pressure up to 180 kbar in boron nitride with zinc-blende structure. The electron and positron wave functions are calculated based on band structures computed using the pseudopotential framework for the electron and the independent particle model for the positron. The shapes of the profiles indicate that the integrated electron–positron momentum densities along [1 1 0] and [0 0 1] crystallographic directions tend to be more flat at the top and their overall values are enhanced when pressure is applied. Possible reasons for this behavior are discussed. The variation of the positron bulk lifetime versus pressure shows a linear-dependence. These results reflect the effect of hydrostatic pressure on positron states in group-III nitrides.