Tuning inter-wall spacing and structural properties of double-walled gallium arsenide nanotubes

The structural, stability and electronic properties of double-walled GaAs nanotubes (DWGaAsNTs) are investigated based on density functional theory (DFT) by considering Van der Waals corrections with the SIESTA code. The computations are done on the zigzag (7,0)@(m,0) and (6,0)@(m,0) with (m = 12 to 18) and the armchair (4,4) @(m,m) and (5,5)@(m,m) DWGaAsNTs with (m = 7 to 14). The calculated binding and formation energies revealed that the armchair and zigzag DWGaAsNTs with differential chirality of 5, (m,m)@(m + 5,m + 5) and 8, (m,0)@(m + 8,0) and inter-layer space of roughly 5.4 and 4.9 & Aring; are the most favorable DWGaAsNTs, respectively. All armchair and zigzag DWGaAsNTs are direct bandgap semiconductors according to the electronic band structure. Furthermore, it is found that with increasing the spaces between walls and diameters of the tubes, the value of the band gap increases, and the changing trend is almost constant at greater distances between walls. Also, the double-walled GaAs nanotubes have a narrower bandgap than single-walled nanotubes. The implications of this research can certainly be useful in future empirical studies.