Structural, electronic and magnetic properties of the 3d transition metal-doped GaN nanotubes

► There are structural distortions around 3d TM ions with respect to pristine GaNNTs. ► The change trend of total magnetic moment follows Hund's rule for doped 3d TM ions. ► Cr, Mn, Fe, Ni-doped (5,5) GaNNTs, Cr, Mn, Ni, Cu-doped (8,0) GaNNTs are half-metals. ► 3d TM-doped GaNNTs may be useful in spintronics and nanomagnets.