Stability and electronic structure of aluminate nanotubes

Abstract

We study the stability and electronic structure of aluminate nanotubes through first-principles theoretical calculations. We find that a tubular structure of aluminates is energetically stable in the form of AlO2, with strain energies smaller than those of MoS2 nanotubes. We find that both zigzag and armchair AlO2 nanotubes are metallic. For zigzag tubes with small diameters, more electron conduction occurs through the outer O shell with longer Al-O bonds while the whole tube wall contributes to electron conduction for large diameter tubes or armchair tubes, which have similar inner and outer Al-O bond lengths. Lithium doping inside the tube cavity can stabilize the tubular form of AlO2 aluminates with metallic conduction, and these nanotubes eventually become semiconducting when heavily doped. On the other hand, although the formation of AlO nanotubes is difficult with Li doping, the tubular structure can be stabilized by hole doping.