Dy2Ti2O7 Spin Ice: a Test Case for Emergent Clusters in a Frustrated Magnet

TL;DR

This paper investigates Dy2Ti2O7 spin ice, revealing that the observed spin clusters are not real entities but artifacts of correlated spin interactions, challenging previous phenomenological models.

Contribution

The study provides a refined microscopic theory including long-range interactions, demonstrating that the apparent clusters are fictitious and result from correlation fine-tuning.

Findings

Clusters are fictitious, not real entities.

Long-range dipolar and exchange interactions are crucial.

Emergent patterns are due to correlation fine-tuning.

Abstract

Dy2Ti2O7 is a geometrically frustrated magnetic material with a strongly correlated spin ice regime that extends from 1 K down to as low as 60 mK. The diffuse elastic neutron scattering intensities in the spin ice regime can be remarkably well described by a phenomenological model of weakly interacting hexagonal spin clusters, as invoked in other geometrically frustrated magnets. We present a highly refined microscopic theory of Dy2Ti2O7 that includes long-range dipolar and exchange interactions to third nearest neighbors and which demonstrates that the clusters are purely fictitious in this material. The seeming emergence of composite spin clusters and their associated scattering pattern is instead an indicator of fine-tuning of ancillary correlations within a strongly correlated state.