Voltage-controlled binary conductance switching in gold-4,4'-bipyridine-gold single-molecule nanowires

TL;DR

This study explores voltage-controlled conductance switching in gold-4,4'-bipyridine-gold single-molecule junctions at cryogenic temperatures, revealing tunable bistability influenced by mechanical and electrical factors.

Contribution

It demonstrates voltage-controlled bistable conductance switching and how switching rates can be modulated by voltage and electrode displacement in single-molecule junctions.

Findings

Conductance switching is bistable and probabilistic.

Electrode displacement controls the dominance of conductance states.

Voltage accelerates switching times exponentially.

Abstract

We investigate gold-4,4'-bipyridine-gold single-molecule junctions with the mechanically controllable break junction technique at cryogenic temperature ($T=4.2\,\text{K}$). We observe bistable probabilistic conductance switching between the two molecular binding configurations, influenced both by the mechanical actuation, and the applied voltage. We demonstrate that the relative dominance of the two conductance states is tunable by the electrode displacement, whereas the voltage manipulation induces an exponential speedup of both switching times. The detailed investigation of the voltage-tunable switching rates provides an insight into the possible switching mechanisms.