Size, dimensionality and composition effects on the Debye temperature of nanocrystals.

As an important property for reflecting the binding forces between atoms, the Debye temperature of nanocrystals can be tuned by size, dimensionality and composition. In order to understand how these factors influence the Debye temperature, in this contribution, a new nanothermodynamic model without any adjustable parameter was established by considering the surface stress and bond number simultaneously. As expected, the Debye temperature decreases with a decrease in size if the dimensionality is given, while the size effect on nanowires is stronger than that on thin films and weaker than that on nanoparticles. It is also found that the Debye temperature of nanoalloys decreases with the increase of the component with smaller cohesive energy for the same size and dimensionality. The validity of the model is proved by the good consistency between the model predictions and experimental and computer simulation results.