Low-temperature scanning probe microscopy using a tuning fork transducer

TL;DR

This paper presents a low-temperature scanning probe microscope utilizing a quartz tuning fork at 4.2 K, enabling charge and magnetic force imaging with a novel approach for coarse positioning and lift-mode scanning.

Contribution

It introduces a low-temperature SPM with a tuning fork transducer, a simple low-temperature walker, and combined charge and magnetic force imaging capabilities.

Findings

Successfully imaged Coulomb forces on boron nanowires

Performed magnetic force imaging at low temperature

Developed a reliable low-temperature coarse approach mechanism

Abstract

We have developed a low-temperature scanning probe microscope using a quartz tuning fork operating at 4.2 K. A silicon tip from a commercial cantilever was attached to one prong of the tuning fork. With a metallic coating, a potential could be applied to the tip to sense the charge distribution in a sample, while with a magnetically coated tip, magnetic force imaging could be performed. For the coarse approach mechanism, we developed a reliable low-temperature walker with low material cost and simple machining. We have obtained Coulomb force images of boron nanowires at room temperature and magnetic nano-structures at low temperature. For lift-mode scanning, we employed a frequency detection mode for the first topographic scan and phase detection mode for the second lift scan.