Y. Min

LOCALIZATION OF THE ENERGY STATES OF LEAD INDUCING THE EFFECT OF RECTIFICATION AND NEGATIVE DIFFERENTIAL RESISTANCE PREDICTED BY FIRST-PRINCIPLES STUDY

The first-principles calculations of the transport characteristics of 4-(5-(2-(5-(4-mercaptophenyl)thiophene-2-yl)ethyl)pyridin-2-yl)benzenethiol sandwiched between two gold leads are performed. The effect of rectification and negative differential resistance (NDR) are obtained, which promise the potential applications in the field of molecular electronics. The rectification effect is 4.49. The peak/valley ratio of the NDR effect is as large as 4.51 for the forward bias and 12.09 for the reverse bias. The strong coupling between gold lead and molecule through thiolate results in the localization of the energy states of gold lead, which may induce the effect of rectification and NDR.

Some methods to regulate low-bias negative differential resistance in σ barrier separating nanoscale molecular transport systems

Using the first-principles method which combines the nonequilibrium Green’s function (NEGF) with density functional theory (DFT), the role of defect, dopant, barrier length and geometric deformation for low-bias negative differential resistance (NDR) in two capped armchair carbon nanotubes (CNTs) sandwiching σ barrier are systematically analyzed. We found that this method can regulate the negative differential resistance (NDR) effects such as current peak and peak position. The adjusting mechanism may originate from orbital interaction and orbital reconstruction. Our calculations try to manipulate the transport characteristics in energy space by simply manipulating the structure in real space, which may promise the potential applications in nanomolecular-electronics in the future.