原子構造体の不安定性解析法とナノ薄膜の理想強度解析への適用

抄録

In order to derive the instability criterion of atomic structures, such as thin film and nano-tube, an analytical method is proposed on the basis of the energy balance against the deformation. Taking into account all degree of freedom for atoms in system, the criterion is given as the positiveness of determinant consisted of the second derivation of energy against the infinitesimal displacement. This method is available for any deformation mode of any atomic structure as well as for any form of interatomic potential. As an application of this method, the ideal tensile strength of thin film is analyzed in order to understand the effect of surface on the instability. Critical stress is successfully extracted by the proposed method combining with the molecular statics simulation. Ideal strength eminently decreases for the films with the thickness of less than 10 nm.