Issue 41, 2019

Identification of vibration modes in single-molecule junctions by strong inelastic signals in noise

Abstract

Conductance measurements in single-molecule junctions (SMJs) are on many occasions accompanied by inelastic spectroscopy and shot-noise measurements in order to obtain information about different vibration modes (or vibrons) and channels involved in the transport respectively. We have extended the single-molecule shot-noise measurements, which were previously performed at low bias, to high bias and we have studied the effects of these vibrons on the noise for a Deuterium (D2) molecule between Pt leads. We report here two important findings from these measurements. First, we find in our noise measurements that at the vibron energies of the molecule, a two-level fluctuation (TLF) is excited in the junction. Second, we show that in the presence of this TLF, a form of enhanced noise spectroscopy can be performed to detect inelastic electron–vibron interactions, by studying the third derivative of the noise (d3SI/dV3). This is possible because TLFs are insensitive to elastic scattering of electrons from defects, which nevertheless leave their signature in the usual inelastic electron tunnelling spectroscopy (IETS) measurements.

Graphical abstract: Identification of vibration modes in single-molecule junctions by strong inelastic signals in noise

Supplementary files

Article information

Article type
Paper
Submitted
08 jul 2019
Accepted
31 aug 2019
First published
06 sep 2019
This article is Open Access
Creative Commons BY-NC license

Nanoscale, 2019,11, 19462-19467

Identification of vibration modes in single-molecule junctions by strong inelastic signals in noise

S. Tewari, C. Sabater and J. van Ruitenbeek, Nanoscale, 2019, 11, 19462 DOI: 10.1039/C9NR05774A

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