Modeling elastic and photoassisted transport in organic molecular wires: length dependence and current-voltage characteristics

Abstract

Using a pi-orbital tight-binding model, we study the elastic and photoassisted transport properties of metal-molecule-metal junctions based on oligophenylenes of varying lengths. The effect of monochromatic light is modeled with an ac voltage over the contact. We first show how the low-bias transmission function can be obtained analytically, using methods previously employed for simpler chain models. In particular, the decay coefficient of the off-resonant transmission is extracted by considering both a finite-length chain and infinitely extended polyphenylene. Based on these analytical results, we discuss the length-dependence of the linear-response conductance, the thermopower, and the light-induced enhancement of the conductance in the limit of weak intensity and low frequency. In general the conductance-enhancement is calculated numerically as a function of the light frequency. Finally, we compute the current-voltage characteristics at finite dc voltages, and show that in the low-voltage regime, the effect of low-frequency light is to induce current steps with a voltage separation determined by twice the frequency. These effects are more pronounced for longer molecules. We study two different profiles for the dc and ac voltages, and it is found that the results are robust with respect to such variations. Although we concentrate here on the specific model of oligophenylenes, the results should be qualitatively similar for many other organic molecules with a large enough electronic gap.

arXiv comment15 pages, 11 figures, minor corrections to old version

References in corpus (29)

• Time-dependent transport in interacting and non-interacting mesoscopic systems
• Dependence of Single Molecule Junction Conductance on Molecular Conformation
• Electron transmission through molecules and molecular interfaces
• Driven quantum transport on the nanoscale
• Photon-assisted transport in semiconductor nanostructures
• Thermoelectric effect in molecular electronics
• Thermal conductance through molecular wires
• Electronics and Chemistry: Varying Single Molecule Junction Conductance Using Chemical Substituents
• Time-dependent quantum transport: A practical scheme using density functional theory
• Scattering Theory of Photon-Assisted Electron Transport
• Electron-vibration interaction in transport through atomic gold wires
• Molecular Wires Acting as Coherent Quantum Ratchets
• Current induced light emission and light induced current in molecular tunneling junctions
• The influence of ultra-fast laser pulses on electron transfer in molecular wires studied by a non-Markovian density matrix approach
• Non-equilibrium GW approach to quantum transport in nano-scale contacts
• Tilt-angle landscapes and temperature dependence of the conductance in biphenyl-dithiol single-molecule junctions
• Electronic transport in Si nanowires: Role of bulk and surface disorder
• Optical properties of current carrying molecular wires
• Thermoelectric effect in molecular junctions: A tool for revealing transport mechanisms
• Influence of chopped laser light onto the electronic transport through atomic-sized contacts
• Conduction in molecular junctions: Inelastic effects
• Coherent laser control of the current through molecular junctions
• Linear optical response of current-carrying molecular junction: A NEGF-TDDFT approach
• Photon-assisted transport in a carbon nanotube
• Photoconductance of organic single-molecule contacts
• Role of electronic structure in photoassisted transport through atomic-sized contacts
• Quantum Transport through Organic Molecules
• Coulomb blockade effects in driven electron transport
• Theoretical study of photon emission from molecular wires

Cited by in corpus (13)

• Length-dependent conductance and thermopower in single-molecule junctions of dithiolated oligophenylene derivatives
• Conduction mechanisms in biphenyl-dithiol single-molecule junctions
• Cluster-based density-functional approach to quantum transport through molecular and atomic contacts
• Mechanical Tuning of Conductance and Thermopower in Helicene Molecular Junctions
• Molecular dynamics study of the thermopower of Ag, Au, and Pt nanocontacts
• Ab-initio study of the thermopower of biphenyl-based single-molecule junctions
• Light-induced current in molecular junctions: Local field and non-Markov effects
• Molecular nanoplasmonics: self-consistent electrodynamics in current carrying junctions
• The effect of fluctuations - thermal and otherwise - on the temperature dependence of thermopower in aromatic chain single-molecule junctions
• Influence of structural disorder and large-scale geometric fluctuations on the Coherent Transport of Metallic Junctions and Molecular Wires
• Electrochemical setup - a unique chance to simultaneously control orbital energies and vibrational properties of single-molecule junctions with unprecedented efficiency
• Photon-assisted electronic and spin transport in a junction containing precessing molecular spin
• Higher harmonics and ac transport from time dependent density functional theory