Sensitivity of gold nano conductors to voids, substitutions and electric field: ab initio results

Abstract

Gold nanowires are good candidates for nanoelectronics devices. A previous study has shown that the beryllium terminated BeO (0001) surface may be a useful platform for supporting nano gold conductors, since it preserves the nano-wire configuration and does not restrict its conductivity. Here, we used ab initio simulations to determine the sensitivity of potential gold nano-conductors to the presence of point defects, O2 substitutions and to an applied perpendicular electric field, as in field effect transistors. We found that the presence of the point defects cause only small changes in the atomic bond lengths of the NW, does not alter the NW configuration, but may affect the overall conductivity. The conductive ability of the conductor depends on the available conductive channels. Single or double voids on the same channel reduce the conductance by 28 % at most, but when the voids arrange in a way that only one channel remains for conductance, it reduces by factor of two to ≈ 1 G0 (G0 = 2e2/h). The presence of a single O2 molecule as a substitution reduces the electron availability in the neighboring Au atoms, in most cases reducing the conductance. The perpendicular electric field, which is typical for field effect transistors, affects the electron density distribution, shifts and changes the conductance spectra profile, but does not decrease the conductivity.