3D Spin Liquid Discovered as A Potential Candidate for Future Information Technologies

May 20, 2020 by Luke James

Researchers have been striving to prove the existence of quantum spin liquids since the 1970s.

These liquids represent a new state of matter and are said to hold potential for lots of useful applications in electronics, IT, and computing. 

These liquids have been something of a mystery since they were first proposed almost five decades ago. If they are proven to exist, however, quantum spin liquids will bring us one step closer to much faster, next-generation quantum computing among other things. 

So far, quantum spin liquids have only usually been found in one- or two-dimensional magnetic systems. Now, an international research team has investigated crystals of PbCuTe2O6—a rare example of a spin liquid ‘candidate’ that features a three-dimensional magnetic lattice—with neutron experiments and claim to have discovered spin three-dimensional spin liquid behavior.

The team’s research, which was published in Nature Communications on May 11, presents a three-dimensional lattice called the hyper-hyperkagome that enables spin liquid behavior and manifests in the PbCuTe2O6 compound. 


Magnetic Interactions Network Triangles 600

A graphical depiction of two magnetic interactions that form a three-dimensional network of corner-sharing triangles. Leading to the quantum spin liquid behavior PbCuTe2O6. Image credited to HZB

What Are Quantum Spin Liquids? 

It is thought by many leading scientists and researchers that the exploitation and development of quantum phenomena will bring about the next breakthrough in electronics, and quantum spin liquid materials are just one of many quantum candidates. They are, as mentioned previously, rare, found primarily in two-dimensional magnetic systems.

Quantum spin liquids are defined by their unusual magnetic arrangement. Magnets have dipoles—a pair of equal and oppositely magnetized poles—that are produced by the quantum spin of electrons.

Inside a magnetic material, dipoles are usually ferromagnetic or antiferromagnetic. In quantum spin liquids, however, dipoles are not as well ordered. Instead, they exhibit unusual ordering within a small distance of one another, and it is this different ordering that creates different types of spin liquids. 


Simulating Magnetic Reactions

Three-dimensional isotropic spin liquids are highly sought in materials where the magnetic ions form hyperkagome lattices, the focus of the Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) research team’s work. 

HZB physicist Professor Johannes Reuther calculated the behavior of such a three-dimensional hyper-hyperkagome lattice with four magnetic interactions and showed that the system exhibits quantum-spin liquid behavior with a specific magnetic energy spectrum.

When neutron experiments were carried out by three different research institutions in the UK, France, and USA, the team was able to prove subtle signals of this calculated behavior. "We were surprised how well our data fit into the calculations. This gives us hope that we can really understand what happens in these systems," explains first author Dr. Shravani Chillal, HZB.