New structural phase obtained by exerting high pressure on (Br2)n@AFI composite material

Abstract

In this paper, we present a theoretical study on the high-pressure behaviors of a (Br2)[Formula: see text]@AlPO4-5 (AFI) peapod structure. The influence of the encapsulated Br2 molecule on the structural deformation of AFI crystal is analyzed using the volume–pressure function. The bonding process of the linearly arrayed Br2 molecule transferring to the bromine atomic chain is analyzed by the electron density distribution. A new high-pressure phase with [Formula: see text] point group symmetry is obtained as the pressure increases to 34 GPa. In addition, electron density difference calculations are used to study the systematic charge transformation. Further analysis indicates that the encapsulated Br2 molecules can significantly modify the electronic structure of the AFI crystal. The band gap of the (Br2)[Formula: see text]@AFI decreases with pressure and closes at 9 GPa. Moreover, the calculated bulk modulus and electronic properties indicate that the new structural phase is metallic with a high hardness, providing a new strategy for exploring novel nanomaterials.