Mechanically activated switching of Si-based single-molecule junction as imaged with three-dimensional dynamic probe

Abstract

Understanding and extracting the full functions of single-molecule characteristics are key factors in the development of future device technologies, as well as in basic research on molecular electronics. Here we report a new methodology for realizing a three-dimensional (3D) dynamic probe of single-molecule conductance, which enables the elaborate 3D analysis of the conformational effect on molecular electronics, by the formation of a Si/single molecule/Si structure using scanning tunnelling microscopy (STM). The formation of robust covalent bonds between a molecule and Si electrodes, together with STM-related techniques, enables the stable and repeated control of the conformational modulation of the molecule. By 3D imaging of the conformational effect on a 1,4-diethynylbenzene molecule, a binary change in conductance with hysteresis is observed for the first time, which is considered to originate from a mechanically activated conformational change.

Conformations of cyclopentasilane stereoisomers control molecular junction conductance

“… 1 – 4 Efforts in molecular electronics have demonstrated the use of silicon surfaces as electrodes 5 – 9 and amino-silanes as chemical binding groups to the electrodes. 10 , 11 Moreover, investigation on cyclohexasilane 12 has shown that conformations affect the molecule's electronic structure and another study on [2,2,2]bicyclic carbosilane systems 13 has suggested that different disilanylene bridges in the cage compounds do not act as parallel resistors. Recently we synthesized linear chains of molecular silicon that demonstrated conductance decay properties comparable to those of π-conjugated hydrocarbons.…”

Many-Body State Description of Single-Molecule Electroluminescence Driven by a Scanning Tunneling Microscope

“…3,4 Furthermore, recent progress in nanometer-scale fabrication techniques combined with optical technologies has allowed optical experiments on current-carrying molecular junctions. [5][6][7][8][9][10][11][12][13][14][15][16][17] These advances bring molecular electronics and optical spectroscopy together, leading to the emergence of molecular optoelectronics. 18,19 In the optical response of current-carrying molecular junctions, the electrons participate in both conductance and optical scattering.…”

Local-noise spectroscopy for nonequilibrium systems

“…Additional spectroscopic tools that have also been employed in non-equilibrium conditions include surface-and tip-enhanced Raman spectroscopy which now allows for measurements on the Angström scale [12][13][14][15][16] , studies of electronic pathways in redox proteins 17 , utilizing 3D dynamic probe of single-molecule conductance to explore conformational changes 18 , and energy-resolved atomic probes 19 , to name just a few.…”