Emergence of negative viscosities and colored noise under current-driven Ehrenfest molecular dynamics

Molecular electronics is a scientific endeavour that, for 60 years, has offered the promise of new technologies in which molecules integrate with, if not entirely replace, semiconductor electronics. En route to the attainment of these ambitious goals, central aspects underpinning the pursuit of this science have proven critical to the development of related technologies, including organic photovoltaics (OPV) and organic light-emitting diodes (OLEDs). Looking ahead, new opportunities in the field abound, from the study of molecular charge transport and the elucidation of molecular reaction mechanisms, to the development of biocompatible and degradable electronics, and the construction of novel chemical sensors with exquisite sensitivity and specificity. This article reviews historical developments in molecular electronics, with a particular focus on Australia’s contributions to the area. Australia’s current activity in molecular electronics research is also summarised, highlighting the capacity to both advance fundamental knowledge and develop new technologies. Scientific aspects considered include capabilities in: single molecule and molecular–monolayer junction measurement; spectroscopic analysis of molecular components and materials; synthetic chemistry; computational analysis of molecular materials and junctions; and the development of theoretical concepts that describe the electrical characteristics of molecular components, materials and putative device structures. Technological aspects considered include various aspects of molecular material design and implementation, such as: OPV and OLED construction, sensing technologies and applications, and power generation from heat gradients or friction. Missing capabilities are identified, and a future pathway for Australian scientific and technological development envisaged.

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“…Effects of current on the natures of molecular junctions, including nonadiabatic effects [242][243][244][245][246][247] James Cook, Daniel Kosov…”

Section: Referencesmentioning

confidence: 99%

Molecular electronics: an Australian perspective

Reimers

Low

2023

Aust. J. Chem.

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A physically realizable molecular motor driven by the Landauer blowtorch effect

Preston

Kosov

2023

The Journal of Chemical Physics

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We propose a model for a molecular motor in a molecular electronic junction driven by a natural manifestation of Landauer’s blowtorch effect. The effect emerges via the interplay of electronic friction and diffusion coefficients, each calculated quantum mechanically using nonequilibrium Green’s functions, within a semiclassical Langevin description of the rotational dynamics. The motor functionality is analyzed through numerical simulations where the rotations exhibit a directional preference according to the intrinsic geometry of the molecular configuration. The proposed mechanism for motor function is expected to be ubiquitous for a range of molecular geometries beyond the one examined here.

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Nonadiabatic dynamics of molecules interacting with metal surfaces: Extending the hierarchical equations of motion and Langevin dynamics approach to position-dependent metal–molecule couplings

Mäck,

Thoss,

Rudge

2024

The Journal of Chemical Physics

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Electronic friction and Langevin dynamics is a popular mixed quantum–classical method for simulating the nonadiabatic dynamics of molecules interacting with metal surfaces, as it can be computationally more efficient than fully quantum approaches. In this work, we extend the theory of electronic friction within the hierarchical equations of motion formalism to models with a position-dependent metal–molecule coupling. We show that the addition of a position-dependent metal–molecule coupling adds new contributions to the electronic friction and other forces, which are highly relevant for many physical processes. Our expressions for the electronic forces within the Langevin equation are valid both in and out of equilibrium and for molecular models containing strong interactions. We demonstrate the approach by applying it to different models of interest.

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Emergence of negative viscosities and colored noise under current-driven Ehrenfest molecular dynamics

Cited by 5 publications

References 75 publications

Molecular electronics: an Australian perspective

Molecular electronics: an Australian perspective

A physically realizable molecular motor driven by the Landauer blowtorch effect

Nonadiabatic dynamics of molecules interacting with metal surfaces: Extending the hierarchical equations of motion and Langevin dynamics approach to position-dependent metal–molecule couplings

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