Electronic behavior in mats of single-walled carbon nanotubes under pressure

TL;DR

This study investigates how the electronic properties of single-walled carbon nanotubes change under high pressure, revealing transitions from semiconducting to metallic and superconducting states.

Contribution

It provides new insights into pressure-induced electronic phase transitions in SWNTs, including evidence of superconductivity at high pressure.

Findings

SWNTs exhibit semiconducting-like behavior at low pressure

Resistance shows Kondo-like features due to magnetic impurities

Superconducting transition observed around 2.4 GPa

Abstract

Single-walled carbon nanotubes (SWNTs) have many interesting properties; they may be metallic or semiconducting depending on their diameter and helicity of the graphene sheet. Hydrostatic or quasi-hydrostatic high pressures can probe many electronic features. Resistance - temperature measurements in SWNTs from normal condition and under 0.4 GPa of quasi-hydrostatic pressures reveal a semiconducting-like behavior. From 0.5 to about 2.0 GPa the resistance changes to a Kondo-like feature due to magnetic impurities used to catalyse the nanotube formation. Above 2.0 GPa, they become metallic and at about 2.4 GPa the resistance decreases dramatically around 3 K suggesting a superconducting transition.