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Title: Voltage equilibration for reactive atomistic simulations of electrochemical processes

We introduce electrochemical dynamics with implicit degrees of freedom (EChemDID), a model to describe electrochemical driving force in reactive molecular dynamics simulations. The method describes the equilibration of external electrochemical potentials (voltage) within metallic structures and their effect on the self-consistent partial atomic charges used in reactive molecular dynamics. An additional variable assigned to each atom denotes the local potential in its vicinity and we use fictitious, but computationally convenient, dynamics to describe its equilibration within connected metallic structures on-the-fly during the molecular dynamics simulation. This local electrostatic potential is used to dynamically modify the atomic electronegativities used to compute partial atomic changes via charge equilibration. Validation tests show that the method provides an accurate description of the electric fields generated by the applied voltage and the driving force for electrochemical reactions. We demonstrate EChemDID via simulations of the operation of electrochemical metallization cells. The simulations predict the switching of the device between a high-resistance to a low-resistance state as a conductive metallic bridge is formed and resistive currents that can be compared with experimental measurements. In addition to applications in nanoelectronics, EChemDID could be useful to model electrochemical energy conversion devices.
Authors:
;  [1]
  1. School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47906 (United States)
Publication Date:
OSTI Identifier:
22493485
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ATOMS; COMPARATIVE EVALUATIONS; DEGREES OF FREEDOM; ELECTRIC FIELDS; ELECTRIC POTENTIAL; ELECTROCHEMICAL ENERGY CONVERSION; ELECTROCHEMISTRY; ELECTRONEGATIVITY; MOLECULAR DYNAMICS METHOD; NANOELECTRONICS; OPERATION; POTENTIALS; VALIDATION