Impact of transition metal dopants (V, Nb, and Ta) on armchair and chiral structured gallium nitride (Ga30N30) nanotubes: A comprehensive DFT study - Bonganur Khan; Aoly Ur Rahman; Md Masud Alam; Noor Ahammad; Md. Alamgir Kabir; Md. Kabir Uddin Sikder (Next Nanotechnology, 2025)