Structural stability and multiple dynamic behaviors of aluminum nanostructures encapsulated in carbon nanotubes

Carbon nanotubes offer one-dimensional nanoconfinement space for metals, resulting in functional materials with novel physical properties. In this study, we successfully predicted a one-dimensional stable structure of aluminum confined within Carbon nanotubes using the MAGUS confined space search method. According to the phonon spectrum, this configuration is mechanically stable at ambient pressure and temperature. However, when the temperature reaches 350 K, aluminum atoms exhibit rotational and translational collective motions, eventually escaping from the open-boundary nanotube. By calculating the diffusion energy barrier of the aluminum, we elucidated the mechanism underlying these collective motion patterns. Through band structure calculations, we discovered strong orbital hybridization between aluminum and Carbon nanotubes. Our research reveals the stable form and unique dynamic and electrical properties of aluminum metal in Carbon nanotubes, providing new insights for the study of metal- Carbon nanotube composites.