Low energy states of a frustrated colloidal ice system

Abstract

A colloidal ice is a system of interacting paramagnetic colloids which are arranged along a lithographic lattice of double wells such that the lattice geometry competes with the pairinteractions and the system generates geometric frustration. In this work, I have used numerical simulations to study this system arranged along a square lattice, where particles are confined in double-well gravitational traps. The double wells are filled each with one particle, and under an external magnetic field the particles can pass the central hill of the traps but never escape from them. The applied field induces repulsive magnetic dipolar interactions and the system try to reach a low energy state. To analyze this state, I have varied the field amplitude, the cut-off distance of the magnetic dipolar interactions and the thermodynamic temperature. Of all of these parameters, I found that both the cut-off distance and the temperature do not influence significantly the evolution of the system towards the low energy states, here measured in terms of the fraction of vertices. In contrast, the field strength allow to reach the system ground state faster