Measurement of the conductance of a hydrogen molecule

TL;DR

This paper reports the measurement of electrical conductance through a single hydrogen molecule bridging platinum electrodes, demonstrating a stable, nearly perfect quantum conductance, advancing understanding in molecular electronics.

Contribution

It provides the first unambiguous measurement of conductance of a single hydrogen molecule in a stable metal-molecule-metal junction.

Findings

Hydrogen molecule forms a stable bridge between Pt electrodes.

The conductance is nearly one quantum unit, indicating a single conduction channel.

This system serves as a fundamental test for molecular electronics.

Abstract

Recent years have shown steady progress in research towards molecular electronics [1,2], where molecules have been investigated as switches [3-5], diodes [6], and electronic mixers [7]. In much of the previous work a Scanning Tunnelling Microscope was employed to address an individual molecule. As this arrangement does not provide long-term stability, more recently metal-molecule-metal links have been made using break junction devices [8-10]. However, it has been difficult to establish unambiguously that a single molecule forms the contact [11]. Here, we show that a single H2 molecule can form a stable bridge between Pt electrodes. In contrast to results for other organic molecules, the bridge has a nearly perfect conductance of one quantum unit, carried by a single channel. The H2-bridge provides a simple test system and a fundamental step towards understanding transport properties of single-molecule devices.