Defect Dynamics in Artificial Colloidal Ice: Real-Time Observation, Manipulation and Logic Gate

TL;DR

This paper investigates defect behavior in a colloidal spin ice system through experiments and simulations, revealing topological monopole-like defects obeying Coulomb law and demonstrating a resettable NOR logic gate for potential nanoscale device applications.

Contribution

It introduces real-time observation and manipulation of defect dynamics in colloidal ice, and demonstrates a nanoscale logic gate based on magnetic monopole motion.

Findings

Defects behave as topological monopoles obeying Coulomb law.

Defects can be manipulated to perform logic operations.

A resettable NOR gate is realized using defect dynamics.

Abstract

We study the defect dynamics in a colloidal spin ice system realized by filling a square lattice of topographic double well islands with repulsively interacting magnetic colloids. We focus on the contraction of defects in the ground state, and contraction/expansion in a metastable biased state. Combining real-time experiments with simulations, we prove that these defects behave like emergent topological monopoles obeying a Coulomb law with an additional line tension. We further show how to realize a completely resettable "NOR" gate, which provides guidelines for fabrication of nanoscale logic devices based on the motion of topological magnetic monopoles.