Large spin-filtering effect in Ti-doped defective zigzag graphene nanoribbon

<p>We theoretically study the conductance of double-vacancy zigzag graphene nanoribbons doped with Ti, V, Cr and Fe, and find that Ti doping, despite possessing small spin moment at Ti site, induces large spin-filtering with an efficiency in excess of 90% for bias voltages below 0.5 V.</p>