Controllable low-bias negative differential resistance and rectifying behaviors induced by symmetry breaking

Incorporating the characteristic of pyramidal electrode and symmetry breaking of molecular structure, we theoretically design a molecular device to perform negative differential resistance and rectifying behaviors simultaneously. The calculated results reveal that low-bias negative differential resistance behaviors can appear symmetrically when tetraphenyl molecule connects to pyramidal gold electrodes. However, as one phenyl of tetraphenyl molecule is replaced by a pyrimidyl, the symmetry breaking on the molecule will break the symmetry of negative differential resistance behavior. The peak-to-valley ratio on negative bias region is larger than that on positive bias region to perform a low-bias rectifying behavior. More importantly, increasing the symmetry breaking can further weaken these two behaviors which propose an effective way to modulate them. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4788691]