Identification of vibration modes in single-molecule junctions by strong inelastic signals in noise. Issue 41 (17th September 2019)

• Record Type: Journal Article
• Authors: Tewari, Sumit; Sabater, Carlos; van Ruitenbeek, Jan
• Is Part Of: Nanoscale. Volume 11:Issue 41(2019)
• Page Start: 19462
• Page End: 19467
• Publication Date: 2019-09-17
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c9nr05774a
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Inelastic electron noise spectroscopy technique combining a high-bias shot noise with vibration-induced two level fluctuations. 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 (d 3 S I /d V 3 ). 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.