Density Functional Study of the Single-Walled Haeckelite AlN Nanotubes in Square-Octagon Structure

In this paper, the stability, electronic properties and vacancy defects of single-walled Haeckelite AlN nanotubes in square-octagon structure (so-AlNNTs) are studied by density functional calculations. The energetic, dynamical, and thermal stability demonstrate the possibility of the formation for so-AlNNTs. Meanwhile, the strain energies of so-AlNNTs also obey the classical elasticity theory. All of the single-walled so-AlNNTs exhibit semiconductor feature. The so-AlNNTs (m, m) have direct gaps, while the so-AlNNTs (m, 0) possess indirect gaps. In addition, the vacancy defects can cause the local structures of so-AlNNTs occurring reorganization. And the so-AlNNTs with vacancy defects are magnetic, which can be applied in the field of spintronics.