Molecular switch controlled by pulsed bias voltages

Abstract

It was observed in recent experiments that the current-voltage characteristics (IV) of BPDN-DT (bipyridyl- dinitro- oligophenylene- ethynylene- dithiol) can be switched in a very controlled manner between "on" and "off" traces by applying a pulse in a bias voltage, V_bias. We have calculated the polaron formation energies to check a frequently held belief, namely, that the polaron formation can explain the observed bistability. Our results are not consistent with such a mechanism. Instead, we propose a conformational reorientation. The molecule carries an intrinsic dipole moment which couples to V_bias. Ramping V_bias exerts a force on the dipole that can reorient ("rotate") the molecule from the ground state ("off") into a metastable configuration ("on") and back. By elaborated electronic structure calculations, we identify a specific path for this rotation through the molecule's conformational phase space. We show that this path has sufficiently high barriers to inhibit thermal instability but still the molecule can be switched in the voltage range of the junction stability. The theoretical IVs reproduce qualitatively the key experimental observations. We propose, how the alternative mechanism of conductance switching can be experimentally verified.

LaTEX, 6 Figures, published version

References in corpus (10)

• Dependence of Single Molecule Junction Conductance on Molecular Conformation
• Single-Molecule Circuits with Well-Defined Molecular Conductance
• Electron transport through single Mn12 molecular magnets
• Charge Transport in Single Au|Alkanedithiol|Au Junctions: Coordination Geometries and Conformational Degrees of Freedom
• Inelastic electron tunneling via molecular vibrations in single-molecule transistors
• Electronic excitations of a single molecule contacted in a three-terminal configuration
• Three-terminal devices to examine single molecule conductance switching
• Bistable molecular conductors with a field-switchable dipole group
• Non-linear response of molecular junctions: The polaron model revisited
• Charge-memory polaron effect in molecular junctions

Cited by in corpus (10)

• Field-induced Conductance Switching by Charge-state Alternation in Organometallic Single-Molecule Junctions
• Resonant Electron Transport in Single-Molecule Junctions: Vibrational Excitation, Rectification, Negative Differential Resistance and Local Cooling
• Irreversibility and hysteresis in redox molecular conduction junctions
• Charge Transport and Conductance Switching of Redox-active Azulene Derivatives
• Vibrationally Induced Decoherence in Single-Molecule Junctions
• Effect of nonadiabatic electronic-vibrational interactions on the transport properties of single-molecule junctions
• Kondo effect in binuclear metal-organic complexes with weakly interacting spins
• Switching the Conductance of a Molecular Junction using a Proton Transfer Reaction
• Hierarchical quantum master equation approach to charge transport in molecular junctions with time-dependent molecule-lead coupling strengths
• Magnetic properties of transition metal dimers probed by inelastic neutron scattering