Strange layer structure of dipolar spins formed on the spin-ice lattice

[Display omitted] •On the computational treatment of long-range dipolar interactions, cutoff and Ewald.•Monte Carlo simulations were performed on the dipolar spin system.•The result showed several correspondences with the other dipolar system, liquid water.•Layer formation occurs from the finite-range cutoff of dipolar interactions. Monte Carlo simulations of dipolar spins on a spin-ice lattice were carried to explore the effect of the long-range interaction. The simulation with finite-range cutoff found formation of a layer-like structure, whereas that with Ewald found no layer. This feature characterized with the dipolar orientation and the distance-dependent Kirkwood factor GK(R) is consistent with that known for water molecular dynamics simulation. This correspondence found between the different systems of water and lattice spin will be important knowledge for understanding the relationship between the long-range interaction and the structure formation.