Single-molecule transport in three-terminal devices

Abstract

Transport through single molecules has been studied using different test beds. In this paper we focus on three-terminal devices in which a molecule bridges the gap between two gold electrodes and a third electrode-the gate-is able to modulate the conduction properties of the junction. Depending on the electronic coupling, , between the molecule and the gold electrodes, different transport regimes can be distinguished. We show measurements on junctions incorporating different single-molecule systems which demonstrate the distinction between these regimes, as well as the experimental limitations in controlling the exact value of .

Spin coupling and relaxation inside molecule–metal contacts

“…Our observations thus indicate that the screened spin is not localized on the metal ion, contrary to conclusions generally drawn from molecular junction experiments [1][2][3] and studies of metal-organic complexes at surfaces 16,18,19,23,24 , but induced by charge transfer into molecular ligand states 13,[25][26][27][28] , independently of the spin of the pristine molecules.…”

“…1c), these peaks coincide with the inelastic conductance steps due to vibrational excitations ( Fig. 1d) and can therefore be assigned to vibrational Kondo events 26 . The coupling mechanism is analogous to that discussed for other aromatic molecules 27,29 .…”

Manipulation of organic polyradicals in a single-molecule transistor

“…[18][19][20] The current, I , was measured as a function of source drain voltage V and gate voltage V g at a temperature T = 2 K. The differential conductance dI/dV was obtained from pointwise linear fits of the I (V ) data.…”

“…2(a) and 2(b), gate-dependent resonances indicate when V is large enough to energetically allow electrons to be added to or removed from the molecule by sequential tunneling. 20 Below these lines, within the so-called Coulomb diamonds, single-electron transport is suppressed and a fixed charge is stabilized by Coulomb blockade. The two crossing points at V = 0 represent charge degeneracies, and by increasing V g going from left to right in Figs.…”

Molecular Junctions: From Tunneling to Function

“…Achieving an electrical functionality therefore consists in observing a conductance modulation effect related for instance to a change in the molecular orbitals arrangement in the junction. For this purpose, it is necessary to implement an additional control using for instance a third electrode [13] or via external stimuli such as light or chemicals, as we will describe below.…”