Electronic Structures of InGaN₂ Nanotubes

We investigate the electronic structures of InGaN₂ nanotubes (NTs) using first-principles calculations. It is found that all four types of InGaN₂ NTs, with the same diameter, have similar stability. The total energy of the per unit InGaN₂ NT depends on its diameter due to the curvature effect. The zigzag (armchair) InGaN₂ NTs have direct (indirect) band gaps. The band gap increases for all of the InGaN₂ NTs when their diameters increase. The valence band maximum (VBM) states of the InGaN₂ NTs are p-like states localised around N atoms. The p-like VBM states in zigzag (armchair) InGaN₂ NTs are perpendicular (parallel) to the tube axis.