Quantum Transport through Asymmetrical Molecular channel Azulene: Role of Orbital Interference

TL;DR

This study explores how quantum interference affects electron transport in azulene molecules with different electrode contacts, revealing how interference patterns influence conductance and I-V characteristics.

Contribution

It provides a detailed analysis of quantum interference effects in azulene molecular junctions with various contact geometries using the non-equilibrium Green's function formalism.

Findings

Configuration 1-3 shows highest conductance due to constructive interference.

Configuration 5-7 exhibits antiresonance and weak conductance.

Asymmetric I-V characteristics are observed in configuration 2-6.

Abstract

We investigate electron transport through azulene molecule with four distinct electrode contact geometries using the non-equilibrium Green's function formalism within the tight-binding Hamiltonian. Employing the Q-matrix approach, we analyze quantum interference (QI) among the molecular orbitals in each contact configuration. Our results reveal distinct transmission profiles and varying current responses among configurations, with the configuration 1-3 displaying the highest conductivity at higher bias due to strong constructive interference of the Highest Occupied Molecular Orbital (HOMO). Conversely, configuration 5-7 exhibit weak conductance and antiresonance at the Fermi energy, attributed to dominant destructive interference among the frontier molecular orbitals. Configuration 2-6 is found to exhibit asymmetric I-V characteristics, due to the dipolar nature of the azulene molecule. These findings underscore the significance of QI effects in shaping the transport properties of azulene, and molecule-based devices in general.