Negative differential resistance in scanning tunneling microscopy: simulations on C$_{60}$-based molecular overlayers

TL;DR

This study uses ab-initio simulations to explore how negative differential resistance (NDR) in C60 molecular devices can be controlled by tuning molecule interactions and bias conditions.

Contribution

It provides a detailed analysis of the bias-dependent electronic properties influencing NDR in C60-based molecular overlayers, revealing how interactions affect device behavior.

Findings

NDR can be modulated by molecule-molecule interactions.

Electronic levels and widths depend on device interactions.

Bias-dependent properties are key to NDR control.

Abstract

We determine the conditions in which negative differential resistance (NDR) appears in the C$_{60}$-based molecular device of [Phys. Rev. Lett. {\bf 100}, 036807 (2008)] by means of ab-initio electron-transport simulations. Our calculations grant access to bias-dependent intrinsic properties of the molecular device, such as electronic levels and their partial widths. We show that these quantities depend on the molecule-molecule and molecule-electrode interactions of the device. Hence, NDR can be tuned by modifying the bias behavior of levels and widths using both types of interactions.