Long-Range Charge Transport in Homogeneous and Alternating-Rigidity Chains

Abstract

We study the interplay of intrinsic-electronic and environmental factors on long-range charge transport across molecular chains with up to $N\sim 80$ monomers. We describe the molecular electronic structure of the chain with a tight-binding Hamiltonian. Thermal effects in the form of electron decoherence and inelastic scatterings are incorporated with the Landauer-Büttiker probe method. In short chains of up to 10 units we observe the crossover between coherent (tunneling, ballistic) motion and thermally-assisted conduction, with thermal effects enhancing the current beyond the quantum coherent limit. We further show that unconventional (non monotonic with size) transport behavior emerges when monomer-to-monomer electronic coupling is made large. In long chains, we identify a different behavior, with thermal effects suppressing the conductance below the coherent-ballistic limit. With the goal to identify a minimal model for molecular chains displaying unconventional and effective long-range transport, we simulate a modular polymer with alternating regions of high and low rigidity. Simulations show that, surprisingly, while charge correlations are significantly affected by structuring environmental conditions, reflecting charge delocalization, the electrical resistance displays an averaging effect, and it is not sensitive to this patterning. We conclude by arguing that efficient long-range charge transport requires engineering both internal electronic parameters and environmental conditions.

References in corpus (19)

• Dependence of Single Molecule Junction Conductance on Molecular Conformation
• Molecular Transport Junctions: Vibrational Effects
• Spin-Selective Transport of Electron in DNA Double Helix
• Fourier's Law for a Harmonic Crystal with Self-consistent Stochastic Reservoirs
• Full counting statistics of vibrationally-assisted electronic conduction: transport and fluctuations of the thermoelectric efficiency
• Vibrational nonequilibrium effects in the conductance of single-molecules with multiple electronic states
• Green's function methods for single molecule junctions
• Electron transport in a one dimensional conductor with inelastic scattering by self-consistent reservoirs
• Quantum heat transfer in harmonic chains with self consistent reservoirs: Exact numerical simulations
• Unified model for conductance through DNA with the Landauer-Buttiker formalism
• Electron-phonon scattering from Green's function transport combined with Molecular Dynamics: Applications to mobility predictions
• Design principles for long-range energy transfer at room temperature
• Machine Learning Prediction of DNA Charge Transport
• Controlling charge transport mechanisms in molecular junctions: Distilling thermally-induced hopping from coherent-resonant conduction
• Phononic heat transport in molecular junctions: quantum effects and vibrational mismatch
• Thermopower of molecular junctions: Tunneling to hopping crossover in DNA
• Inelastic effects in molecular transport junctions: The probe technique at high bias
• From exhaustive simulations to key principles in DNA nanoelectronics
• Charge transport in a multi-terminal DNA tetrahedron: Interplay among contact position, disorder, and base-pair mismatch