Factors to determine the pressure change tendencies in pressure-induced phase transition of semiconductor nanocrystals

•Size-dependent phase transition pressure for nanocrystals is discussed.•Variation tendencies of phase transition pressure can be determined.•Surface energy, surface stress and gram-atom volume are the decisive parameters.•Individual contributions of surface energy and surface stress are clarified.•Model predictions agree well with the experimental and theory results.

A critical rule without free parameters to estimate the size-dependent enhancement or reduction of phase transition pressure ΔPe(D) for phase transitions of nanocrystals is established where D denotes the size of nanocrystals. ΔPe(D) function is determined by D, surface energy γ, surface stress f and gram-atom volume Vg of the two transition phases. Also, the individual contributions of γ and f on ΔPe(D) can be separated. Our model predictions agree well with the corresponding experimental and theoretical results. This model is of fundamental significance in understanding the essence of size-dependent pressure induced phase transition and guiding the experimental scientists to estimate their results.