Probing local electric field and conformational switching in single-molecule break junctions

Rahimi, Maryam; Troisi, Alessandro

doi:10.1103/physrevb.79.113413

Cited by 15 publications

(14 citation statements)

References 34 publications

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“…The vast stereoelectronics knowledge base can therefore serve as a tremendous resource in controlling electronics at the single-molecule level by directing molecular conformation. Although conformational effects have been reported in other single-molecule devices, none of these reported components have demonstrated digital switching between conductance states by controlling bond rotation, as is shown here [10][11][12][13][14][15] .…”

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confidence: 79%

Stereoelectronic switching in single-molecule junctions

et al. 2015

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A new intersection between reaction chemistry and electronic circuitry is emerging from the ultraminiaturization of electronic devices. Over decades chemists have developed a nuanced understanding of stereoelectronics to establish how the electronic properties of molecules relate to their conformation; the recent advent of single-molecule break-junction techniques provides the means to alter this conformation with a level of control previously unimagined. Here we unite these ideas by demonstrating the first single-molecule switch that operates through a stereoelectronic effect. We demonstrate this behaviour in permethyloligosilanes with methylthiomethyl electrode linkers. The strong σ conjugation in the oligosilane backbone couples the stereoelectronic properties of the sulfur-methylene σ bonds that terminate the molecule. Theoretical calculations support the existence of three distinct dihedral conformations that differ drastically in their electronic character. We can shift between these three species by simply lengthening or compressing the molecular junction, and, in doing so, we can switch conductance digitally between two states.

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confidence: 79%

Stereoelectronic switching in single-molecule junctions

et al. 2015

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“…[68][69][70] As described in the MCBJ section, Raman spectra and inelastic electron tunneling spectroscopy can supply a large amount of information about the configuration of the molecule in the EBJ produced gaps. [71][72][73][74] 2.4. Self-assembly of nanostructures…”

Section: Electromigration Break Junctions (Ebjs)mentioning

confidence: 99%

Single-molecule electronics: from chemical design to functional devices

et al. 2014

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The use of single molecules in electronics represents the next limit of miniaturisation of electronic devices, which would enable us to continue the trend of aggressive downscaling of silicon-based electronic devices. More significantly, the fabrication, understanding and control of fully functional circuits at the single-molecule level could also open up the possibility of using molecules as devices with novel, not-foreseen functionalities beyond complementary metal-oxide semiconductor technology (CMOS). This review aims at highlighting the chemical design and synthesis of single molecule devices as well as their electrical and structural characterization, including a historical overview and the developments during the last 5 years. We discuss experimental techniques for fabrication of single-molecule junctions, the potential application of single-molecule junctions as molecular switches, and general physical phenomena in single-molecule electronic devices.

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“…These IETS experiments and comparison with the theoretical work have demonstrated conclusively that particular molecular species are involved in electrical conduction through metal-molecule-metal junctions by exploiting the fact that the measured phonon ener-gies provide a fingerprint of the molecule involved in the conduction process. The effects of changes in the molecular conformation [32,41,77] and in the orientation of molecules relative to the electrodes [59,79] on the inelastic tunneling spectra have also been studied. However, the possibility that IETS might identify the bonding geometries at the molecule-metal interfaces and thus resolve the long standing "contact problem" of determining the atomic scale structure of the molecule-electrode interfaces has only very recently begun to be explored.…”

Section: Introductionmentioning

confidence: 99%

Identification of the atomic scale structures of the gold-thiol interfaces of molecular nanowires by inelastic tunneling spectroscopy

Demir

Kirczenow

2012

The Journal of Chemical Physics

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We examine theoretically the effects of the bonding geometries at the gold-thiol interfaces on the inelastic tunneling spectra of propanedithiolate (PDT) molecules bridging gold electrodes and show that inelastic tunneling spectroscopy combined with theory can be used to determine these bonding geometries experimentally. With the help of density functional theory, we calculate the relaxed geometries and vibrational modes of extended molecules each consisting of one or two PDT molecules connecting two gold nanoclusters. We formulate a perturbative theory of inelastic tunneling through molecules bridging metal contacts in terms of elastic transmission amplitudes, and use this theory to calculate the inelastic tunneling spectra of the gold-PDT-gold extended molecules. We consider PDT molecules with both trans and gauche conformations bound to the gold clusters at top, bridge, and hollow bonding sites. Comparing our results with the experimental data of Hihath et al. [Nano Lett. 8, 1673 (2008)], we identify the most frequently realized conformation in the experiment as that of trans molecules top-site bonded to both electrodes. We find the switching from the 42 meV vibrational mode to the 46 meV mode observed in the experiment to be due to the transition of trans molecules from mixed top-bridge to pure top-site bonding geometries. Our results also indicate that gauche molecular conformations and hollow site bonding did not contribute significantly to the experimental inelastic tunneling spectra. For pairs of PDT molecules connecting the gold electrodes in parallel we find total elastic conductances close to twice those of single molecules bridging the contacts with similar bonding conformations and small splittings of the vibrational mode energies for the modes that are the most sensitive to the molecule-electrode bonding geometries.

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Probing local electric field and conformational switching in single-molecule break junctions

Cited by 15 publications

References 34 publications

Stereoelectronic switching in single-molecule junctions

Stereoelectronic switching in single-molecule junctions

Single-molecule electronics: from chemical design to functional devices

Identification of the atomic scale structures of the gold-thiol interfaces of molecular nanowires by inelastic tunneling spectroscopy

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