Liquid-induced damping of mechanical feedback effects in single electron tunneling through a suspended carbon nanotube

TL;DR

This study investigates how liquid environments influence mechanical feedback effects in single electron tunneling through suspended carbon nanotubes, revealing that viscous liquids suppress vibrational switching phenomena and enable alternative spectroscopic methods.

Contribution

It demonstrates that immersing nanotubes in viscous liquids like helium suppresses vibrational effects, allowing for finite bias spectroscopy without mechanical interference.

Findings

Switching phenomena are absent in viscous liquids.

Liquid helium environment enables alternative spectroscopy.

Mechanical effects are suppressed in viscous media.

Abstract

In single electron tunneling through clean, suspended carbon nanotube devices at low temperature, distinct switching phenomena have regularly been observed. These can be explained via strong interaction of single electron tunneling and vibrational motion of the nanotube. We present measurements on a highly stable nanotube device, subsequently recorded in the vacuum chamber of a dilution refrigerator and immersed in the 3He/4He mixture of a second dilution refrigerator. The switching phenomena are absent when the sample is kept in the viscous liquid, additionally supporting the interpretation of dc-driven vibration. Transport measurements in liquid helium can thus be used for finite bias spectroscopy where otherwise the mechanical effects would dominate the current.