Connectivity-Dependent Attenuation Factor in Nanographene-Based Molecular Wires

TL;DR

This paper introduces a new class of nanographene molecular wires with a dual attenuation factor, where conductance can increase or decrease with length depending on electrode connection, enabling tailored molecular circuitry.

Contribution

It reveals the inherent dual attenuation property of graphene-like nanowires and links conductance behavior to quantum interference patterns based on connectivity.

Findings

Conductance can increase or decrease with length depending on connection points.

Dual attenuation factor is an inherent property of nanographene wires.

Quantum interference determines conductance behavior.

Abstract

Designing molecular nanowires with high electrical conductance that facilitate efficient charge transport over long distances is highly desirable for future molecular-scale circuitry. However, most molecular wires act as tunnel barriers, and their electrical conductance decays exponentially with increasing length. Only recently have a few studies shown increasing conductance with length. In this study, we identify a new class of molecular wires that exhibit both an increase and a decrease in room-temperature conductance with length (a dual attenuation factor), depending on their connection points to the electrodes. We show that this dual attenuation factor is an inherent property of these graphene-like nanowires, and its demonstration depends on the constructive quantum interference pattern for different connectivities to the electrodes. This is significant because a given nanographene molecular wire can show both negative and positive attenuation factors. This enables the systematic design of connectivity-dependent high/low-conductance molecular wires for future molecular-scale circuitry.