Atom-by-atom extraction using scanning tunneling microscope tip-cluster interaction

TL;DR

This study demonstrates atom-by-atom extraction from a silver cluster using an STM tip, revealing how tip proximity influences the extraction barrier and enabling precise, reproducible atomic manipulation at cryogenic temperatures.

Contribution

It introduces a detailed understanding of atom extraction mechanics via STM tip-cluster interaction, combining experiments with energy calculations and simulations.

Findings

Extraction occurs at low bias and specific resistance thresholds.

Proximity tuning lowers the atom extraction barrier.

Repeated, precise atom removal from clusters is achievable.

Abstract

We investigate atomistic details of a single atom extraction process realized by using scanning tunneling microscope (STM) tip-cluster interaction on a Ag(111) surface at 6 K. Single atoms are extracted from a silver cluster one atom at a time using small tunneling biases less than 35 mV and a threshold tunneling resistance of 47 kOhm. A combination of total energy calculations and molecular dynamics simulations shows a lowering of the atom extraction barrier upon approaching the tip to the cluster. Thus, a mere tuning of the proximity between the tip and the cluster governs the extraction process and is sufficient to extract an atom. The atomically precise control and reproducibility of the process are demonstrated by repeatedly extracting single atoms from a silver cluster on an atom-by-atom basis.