Self-Assembly of a Two-Dimensional Sheet with Ta@Si16 Superatoms and Its Magnetic and Photocatalytic Properties

The development of new functional materials with a rational design, controllable assembly, and tunable property is highly demanded. Here, we take the experimentally synthesized Ta@Si-16 superatom as a building block to design several low-lying Ta@Si-16 dimers and self-assembled two-dimensional (2D) sheets, and then study their structural stability and magnetic and photocatalytic properties as well as potential applications by density functional theory and molecular dynamics. Our results show that the Ta@Si-16 superatom can maintain its cage frame of geometric structure in all of these self-assembled structures at room temperature. It is found that the honeycomb hexagonal lattice Hex-d structure, the line-contact and the face-contact Ta@Si-16/C-60 interfacial structures are three new semiconductors with band gaps of 0.89, 0.43, and 1.32 eV, respectively. As an intrinsic ferromagnet, the line-contact Ta@Si-16/C-60 structure has a Curie temperature of 294 K. Furthermore, our study shows that the face-contact Ta@Si-16/C-60 one might be a good photocatalyst.