Resonant transport in a highly conducting single molecular junction via metal-metal covalent bond.
Biswajit PabiŠtepán MarekAdwitiya PalPuja KumariSoumya Jyoti RayArunabha ThakurRichard KorytárAtindra Nath PalPublished in: Nanoscale (2023)
Achieving highly transmitting molecular junctions through resonant transport at low bias is key to the next-generation low-power molecular devices. Although resonant transport in molecular junctions was observed by connecting a molecule between the metal electrodes via chemical anchors by applying a high source-drain bias (>1 V), the conductance was limited to <0.1 G 0 , G 0 being the quantum of conductance. Herein, we report electronic transport measurements by directly connecting a ferrocene molecule between Au electrodes under ambient conditions in a mechanically controllable break junction setup (MCBJ), revealing a conductance peak at ∼0.2 G 0 in the conductance histogram. A similar experiment was repeated for ferrocene terminated with amine (-NH 2 ) and cyano (-CN) anchors, where conductance histograms exhibit an extended low conductance feature, including the sharp high conductance peak, similar to pristine ferrocene. The statistical analysis of the data and density functional theory-based transport calculation suggest a possible molecular conformation with a strong hybridization between the Au electrodes, and that the Fe atom of ferrocene is responsible for a near-perfect transmission in the vicinity of the Fermi energy, leading to the resonant transport at a small applied bias (<0.5 V). Moreover, calculations including van der Waals/dispersion corrections reveal a covalent-like organometallic bonding between Au and the central Fe atom of ferrocene, having bond energies of ∼660 meV. Overall, our study not only demonstrates the realization of an air-stable highly transmitting molecular junction, but also provides important insights about the nature of chemical bonding at the metal/organo-metallic interface.
Keyphrases
- density functional theory
- single molecule
- molecular dynamics
- reduced graphene oxide
- machine learning
- squamous cell carcinoma
- magnetic resonance imaging
- air pollution
- single cell
- gene expression
- electronic health record
- magnetic resonance
- deep learning
- room temperature
- electron transfer
- monte carlo
- visible light
- diffusion weighted imaging
- transition metal