AlSi2P nanotubes: a theoretical study

The geometry, stability, and structural properties of single-walled AlSi 2 P nanotubes were investigated by the first-principles density functional calculations. Considering different arrangements of AlP and SiSi units, three types of zigzag (ZZ-1, ZZ-2, and ZZ-3) ( n , 0), n = 3, 4, and 5, and two types of armchair (AC-1 and AC-2) ( n , n ) AlSi 2 P nanotubes, n = 4, 5, and 6, were constructed. The present calculations show that, in general, there is a tendency toward the formation of alternate –Si–Si– and –Al–P– chains in the most stable AlSi 2 P nanotubes. Due to the high tendency of P and Si atoms to adopt sp 3 hybridization, silicon and phosphorus atoms somewhat pop outward, while Al atoms prefer stable sp 2 hybridization and form planar structure on the tube surface. Such structural features in the optimized geometry of the AlSi 2 P nanotubes lead to amazing structures such as the periodic bamboo-like structure of the ZZ-1( n , 0) AlSi 2 P nanotubes and “polygonal” cross section in the ZZ-3( n , 0) and AC-1( n , n ) AlSi 2 P nanotubes. It is expected that the high point charges calculated on Al atoms, ranging from +0.839 to +1.021, and P atoms, ranging from −0.561 to −0.949, establish an overall charge transfer on the surface of nanotubes. Graphical Abstract AlSi 2 P nanotubes