Fluctuation-induced spin nematic order in magnetic charge-ice

TL;DR

This paper explores how strong, correlated disorder in charge-ice materials induces a transition from an algebraic spin liquid to a spin nematic phase, revealing new magnetic behaviors driven by structural disorder.

Contribution

It demonstrates that correlated disorder in charge-ice can lead to a fluctuation-induced spin nematic order, linking structural disorder to magnetic phase transitions.

Findings

Disorder creates correlated loops of cations affecting magnetic interactions.

A transition from spin liquid to spin nematic occurs at low temperatures.

The transition's nature depends on the loop statistics, offering thermodynamic signatures.

Abstract

Disorder in materials may be used to tune their functionalities, but much more strikingly, its presence can entail entirely new behavior. This happens in charge-ice where structural disorder is not weak and local, but strong and long-range correlated. Here, two cations of different charge occupy a pyrochlore lattice, arranging themselves such that all tetrahedra host two cations of each type. The ensuing correlated disorder is characterized by randomly packed loops of a single cation-type. If the cations are magnetic and interact antiferromagnetically, a new type of magnet with strong interactions along the loops, but frustrated interactions between loops, emerges. This results in an ensemble of intertwined Heisenberg spin chains that form an algebraic spin liquid at intermediate temperatures. At lower temperatures, we find these non-local degrees of freedom undergo a discontinuous transition to a spin nematic. While this phase does not break time reversal symmetry, its spin symmetry is reduced resulting in a dramatically slower spin relaxation. The transition is sensitive to the statistics of the cation loops, providing both a direct thermodynamic signature of otherwise elusive structural information and a structural route to engineering nematic phase stability.