  Water confined between two layers with separation of a few Angstrom forms
layered two- dimensional ice structure. Using large scale molecular dynamics
simulations with the adoptable ReaxFF interatomic potential we found that flat
monolayer ice with a rhombic-square structure nucleates between graphene layers
which is non-polar and non-ferroelectric. Two layers of water are found to
crystallize into a square lattice close to the experimental found AA-stacking
[G. Algara- Siller et al. Nature 519, 443445 (2015)]. Each layer has a net
dipole moment which are in opposite direction. Bilayer ice is also non-polar
and non-ferroelectric. For three layer ice we found that each layer has a
crystal structure similar to monolayer ice.
