Molecularly inherent voltage-controlled conductance switching

Abstract

Molecular electronics has been proposed as a pathway for high-density nanoelectronic devices. This pathway involves the development of a molecular memory device based on reversible switching of a molecule between two conducting states in response to a trigger, such as an applied voltage. Here we demonstrate that voltage-triggered switching is indeed a molecular phenomenon by carrying out studies on the same molecule using three different experimental configurations-scanning tunnelling microscopy, crossed-wire junction, and magnetic-bead junction. We also demonstrate that voltage-triggered switching is distinctly different from stochastic switching, essentially a transient (time-dependent) phenomenon that is independent of the applied voltage.

Possible performance improvement in [2]catenane molecular electronic switches

“…Such statistical consideration is essential in molecular electronics where the flexible nature of molecules and the indeterminacy of molecule-electrode interfaces significantly hamper the identification of a truly molecular switching signal. 11 For each GSCC and MSCC configuration, we carried out two independent MD simulations and from each run we selected four random configurations at the 10 ps time interval to prepare eight molecular structures. As shown in Figs Before discussing Fig.…”

“…While the voltage-gated conformational change of the molecules between the off-state GSCC and the on-state MSCC was proposed as the switching mechanism, 3-6 the molecular origin of the switching was questioned 7 as seemingly contradictory experiments appeared. [8][9][10] Indeed, differentiating a molecularly inherent switching from a stochastic one is a difficult task, 11 because the charge transport in molecular scale junctions is strongly influenced by the moleculeelectrode contacts and conformational fluctuations of molecules. [12][13][14][15] In a recent work, 16 employing realistic catenane monolayer models sandwiched between Au͑111͒ electrodes , we explicitly showed that the electrical switching ͑between on and off͒ can originate from the energetic movement of frontier orbitals that accompanies the structural switching of the molecule ͑between GSCC and MSCC, respectively͒.…”

Nanogap Electrodes

“…The molecular-based devices possess unique advantages for electronic applications, [3] such as lower cost, lower power dissipation, higher efficiency, ability of self-assembly and recognition, distinct optical and electronic properties, and synthetic tailoring ability by elaborate choice of geometry and composition. A variety of specific electronic functions performed by single molecules, including rectifiers, [4,5] switches [6,7] and transistors, [8][9][10] have been accordingly designed and reported. All the above aspects render molecules as ideal candidates for the next generation of electronics.…”

“…[6] All devices manufactured by this kind of method can be categorized as 'prototype devices', which are very useful for fundamental investigations and have already provided many important results. [4][5][6][7][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] However, these devices are far from practical applications, as we can not imagine a nanometer device carrying a huge scanning probe microscopy (SPM) system or other systems. The other way utilizes nanogap electrodes [28][29][30][31][32] to form metal/molecule/metal devices.…”

Numerically exact, time-dependent treatment of vibrationally coupled electron transport in single-molecule junctions

“…The experiments have also revealed a wealth of interesting transport phenomena including Coulomb blockade, 13 Kondo effect, 29 negative differential resistance, 26,30,31 switching, and hysteresis. [32][33][34] Furthermore, the possibility to obtain transport characteristics that resemble those of a diode 20 or a transistor 11 has been demonstrated. These findings have stimulated great interest in the basic mechanisms which govern quantum transport at the molecular scale.…”