Finite electric displacement simulations of polar ionic solid-electrolyte interfaces: Application to NaCl(111)/aqueous NaCl solution.
Publication Date
2019-01Journal Title
The Journal of chemical physics
ISSN
0021-9606
Publisher
AIP Publishing
Volume
150
Issue
4
Pages
041716
Language
eng
Type
Article
This Version
AM
Physical Medium
Print
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Sayer, T., Sprik, M., & Zhang, C. (2019). Finite electric displacement simulations of polar ionic solid-electrolyte interfaces: Application to NaCl(111)/aqueous NaCl solution.. The Journal of chemical physics, 150 (4), 041716. https://doi.org/10.1063/1.5054843
Abstract
Tasker type III polar terminations of ionic crystals carry a net surface charge as well as a dipole moment and are fundamentally unstable. In contact with electrolytes, such polar surfaces can be stabilized by adsorption of counter ions from solution to form electric double layers (EDLs). In a previous work (J. Chem. Phys 147, 104702 (2017)) we reported on a classical force field based molecular dynamics study of a prototype model system namely a NaCl(111) slab interfaced with an aqueous NaCl solution on both sides. A serious hurdle in the simulation is that the finite width of the slab admits an electric field in the solid perturbing the theoretical charge balance at the interface of semi-infinite systems (half the surface charge density for NaCl(111)). It was demonstrated that the application of a finite macroscopic field $E$ cancelling the internal electric field can recover the correct charge compensation at the interface. In the present work, we expand this method by applying a conjugate electric displacement field $D$. The benefits of using $D$ instead of $E$ as the control variable are two fold: it does not only speed up the convergence of the polarization in the simulation but also leads to a succinct expression for the biasing displacement field involving only structural parameters which are known in advance. This makes it feasible to study the charge compensating phenomenon of this prototype system with density functional theory based molecular dynamics (DFTMD), as shown in this work.
Sponsorship
EPSRC (EP/P022596/1)
EPSRC (1800796)
Identifiers
External DOI: https://doi.org/10.1063/1.5054843
This record's URL: https://www.repository.cam.ac.uk/handle/1810/287644
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