A First Principles Study of Ultra-Thin (AIO) n Nanorods: Mechanical Behaviour Under Tension and Compression

Abstract

A first principles approach based on the density functional theory (DFT) was used to study the mechanical behaviour of the linear (Al-O) _n nanorods with n spanned 1 to 10. The minimum-energy configurations for the nanostructures are first found by fully relaxing the coordinates of the atoms. Virtual tension and compression tests were then conducted by applying a series of tensile/compressive deformations to the relaxed structures and calculating the corresponding forces required to maintain the equilibrium of the deformed nanorods. A force-strain curve is then obtained for all the nanorods from these virtual tests. The mechanical response of the two shortest nanorods is similar to that of the ductile aluminium, but the longer nanorods deform in a similar manner to the brittle aluminium oxide. All the nanorods demonstrate a much higher compressive strength than tensile strength.