Two limits of melting temperatures of nanocrystals

It is demonstrated that the melting temperature of nanocrystals embedded in a matrix exhibit two asymptotic limits as the size of the nanocrystal reac hes its smallest value. The lower limit of melting temperatures is related to the disappearance of size-dependent entropy of melting and is considered as the lowest glass transition temperature which is located between Kauzma nn temperature and glass transition temperature. The upper limit of a nanoc rystal embedded in a matrix is determined by the ratio between the bulk mel ting temperature of the embedded nanocrystal and that of the matrix. The pr edicted thermodynamic melting temperature range and the lowest glass transi tion temperature are supported by available experimental evidences. (C) 199 9 Kluwer Academic Publishers.