Dielectric Profile and Electromelting of a Monolayer of Water Confined in Graphene Slit Pore*

Monolayer confined water between parallel graphene sheets exists in many different phases and exhibits fascinating dielectric properties that have been studied in experiments. We use molecular dynamics simulations to study how the dielectric properties of a confined monolayer of water is affected by its structure. Considering six nonpolarizable water models we investigate the role of the in-plane water structure on its dielectric profile. We find that models which do not exhibit ice formation show very different dielectric response along the channel width compared to models that exhibit square ice formation. We also demonstrate the occurrence of electromelting of the in-plane ordered water under the application of a perpendicular electric field and find the model-dependent critical field values. Together, we have shown the strong dependence of confined water properties on the different water structures that can be exploited in various nanofluidic devices, artificial ion channels, and molecular sieving.