Complete spin polarization for a carbon nanotube with an adsorbed atomic transition-metal chain

Our calculations indicate that a chromium or vanadium atomic chain adsorbed on an armchair carbon nanotube opens up a band gap for the minority spin, making the whole system a 100% spin-polarized conductor. The gaps are 0.49 and 0.44 eV for V and Cr, respectively. The adsorption of manganese, iron, cobalt, or nickel chains leads to large but not complete spin polarization. These hybrid structures can function as basic building blocks for the nanoscale construction of hitherto elusive perfect spin polarizers, which promise wide-ranging applications in spintronics research.