Site-selective conductance of sidewall functionalized carbon nanotubes

TL;DR

This study uses DFT to analyze how different molecular adsorbates affect the conductance of metallic carbon nanotubes, revealing conditions under which conductance channels are preserved or blocked.

Contribution

It provides a detailed analysis of how specific molecular adsorbates influence conductance channels in carbon nanotubes, introducing geometric conditions for channel preservation.

Findings

Single molecule adsorption suppresses one conductance channel.

Adsorbate position determines whether remaining channels are blocked.

Geometric conditions can preserve conductance channels despite multiple adsorptions.

Abstract

We use DFT to study the effect of molecular adsorbates on the conductance of metallic carbon nanotubes. The five molecules considered (NO2, NH2, H, COOH, OH) lead to similar scattering of the electrons. The adsorption of a single molecule suppresses one of the two available channels of the CNT at low bias conductance. If more molecules are adsorbed on the same sublattice, the remaining open channel can be blocked or not, depending on the relative position of the adsorbates. If a simple geometric condition is fulfilled this channel is still open, even after adsorbing an arbitrary number of molecules.