Field emission properties of carbon nanowires from ab initio calculations

The field emission (FE) characteristics of linear carbon chains, relevant for understanding FE properties of complex carbon-based nanostructures, are studied by means of self-consistent density functional calculations in the presence of a constant electric held, making use of pseudopotentials and the local density approximation (LDA). The transmission coefficient for electron tunneling through the LDA potential barrier to the vacuum is obtained within the WKB approximation. It is found that chain polarization has remarkable effects on the emission properties, yielding currents of the order of 1 mu A for a chain of 9 atoms under standard bias conditions. Such carbon chains may thus be seen as the atomic scale realization of metallic nanowires.