Scientists from Boston College and Harvard University have created a first-of-its-kind copper iridate metal oxide, in which the natural magnetic order is disrupted, by conducting a copper ‘exchange’ reaction with sodium iridate. Image: Boston College.
Scientists from Boston College and Harvard University have created a first-of-its-kind copper iridate metal oxide, in which the natural magnetic order is disrupted, by conducting a copper ‘exchange’ reaction with sodium iridate. Image: Boston College.

Researchers from Boston College and Harvard University have created an elusive honeycomb-structured material capable of frustrating the magnetic properties within it in order to produce a chemical entity known as a ‘spin liquid’. According to a paper on this work in the Journal of the American Chemical Society, this entity has long been theorized as a gateway to the free-flowing properties of quantum computing.

The honeycomb-structured material is a first-of-its-kind copper iridate metal oxide – Cu2IrO3 – in which the natural magnetic order is disrupted, a state known as geometric frustration, said Fazel Tafti, an assistant professor of physics at Boston College and lead author of the paper.

The copper iridate is an insulator – its electrons are immobilized in the solid – but they can still transport a magnetic moment known as ‘spin’. The transport of free spins in the material allows for a flow of quantum information.

The Kitaev model, proposed in 2006 by Alexei Kitaev at Caltech, predicted that a hexagonal honeycomb structure offered a promising route to geometric frustration and, therefore, to a quantum spin liquid. Up to now, only two honeycomb lattices have been developed in an attempt to fulfill Kitaev's model: a lithium iridate (Li2IrO3) and a sodium iridate (Na2IrO3). Yet both fell short of achieving an ideal spin liquid due to magnetic ordering.

To develop their honeycomb lattice, Tafti and his team turned to copper due to its ideal atomic size, which is between lithium and sodium. Using x-ray crystallography, they found subtle flaws in the honeycombs formed by the lithium and sodium iridates, and so they swapped copper for sodium in what Tafti termed a relatively simple ‘exchange’ reaction. This effort produced the first oxide of copper and iridium.

"Copper is ideally suited to the honeycomb structure," explained Tafti. "There is almost no distortion in the honeycomb structure."

A decade after the original prediction of quantum spin liquid on a honeycomb lattice by Kitaev, Tafti and his colleagues have succeeded in making a material that almost exactly corresponds to the Kitaev model. Tafti's lab will now pursue the ‘exchange’ chemistry path to make new forms of honeycomb materials with more exotic magnetic properties, he said.

This story is adapted from material from Boston College, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.