Enhanced metallicity and spin polarization in zigzag graphene nanoribbons with Fe impurities

• Fe impurities exhibit stable bonding with zigzag graphene nanoribbons (ZGNR).
• Stability and electronic properties are sensitive to doping site rather than ribbon width.
• Fe interaction makes ZGNR a magnetic metal irrespective of the ribbon widths.
• A high spin polarization (upto 95%) is observed particularly for Fe passivated ZGNR.

We present the first principles calculations of zigzag graphene nanoribbons (ZGNR), passivated and substitutionally doped with Fe atoms. The structural stability, electronic structures and transport properties have been discussed within the frame work of density functional theory. Present calculations revealed that ribbons with a single Fe impurity per unit cell exhibit magnetic ground state independent of the site of impurity atom. All the structures have stable binding and one-edge Fe-passivated ZGNR is the most stable configuration in contrast to other considered structures including the pristine one. The electronic properties are found sensitive to the impurity site rather than the GNR width. Our findings include the possibility of converting pristine ZGNR into highly conducting ribbons which can also sustain the spin polarized current. A high spin polarization (up to 95%) has been achieved which pledges for its potential application in spintronic devices.

The variation of current against applied voltage for various configurations of zigzag graphene nanoribbons (ZGNR).Fe impurity can turn ZGNR into magnetic metals. Observed metallicity and spin polarization are sensitive to the site of Fe-impurity rather than the ribbon width.Figure optionsDownload as PowerPoint slide