Monday, December 6, 2021

Quantum Computing: "Artificial material mimics rare earth compounds"

Materials science has seemed to be on the verge of its own Cambrian explosion for the last ten years.

Maybe now is the time, but who knows?


Physicists have created a new ultra-thin, two-layer material with quantum properties that normally require rare earth compounds.

In a paper published in the journal Nature, the scientists explain that this material, which is relatively easy to make and does not contain rare earth metals, could provide a new platform for quantum computing. It could also help advance research into unconventional superconductivity and quantum criticality.

In detail, the researchers showed that by starting from seemingly common materials, a radically new quantum state of matter can appear.

The discovery emerged from their efforts to create a quantum spin liquid which they could use to investigate emergent quantum phenomena such as gauge theory. This involves fabricating a single layer of atomically thin tantalum disulphide, but the process also creates islands that consist of two layers.

When the team based at Finland’s Aalto University examined these islands, they found that interactions between the two layers induced a phenomenon known as the Kondo effect, leading to a macroscopically entangled state of matter producing a heavy-fermion system.

The Kondo effect is an interaction between magnetic impurities and electrons that causes a material’s electrical resistance to change with temperature. This results in the electrons behaving as though they have more mass, leading these compounds to be called heavy-fermion materials. This phenomenon is a hallmark of materials containing rare earth elements.

Heavy-fermion materials are important in several domains of cutting-edge physics, including research into quantum materials.

“Studying complex quantum materials is hindered by the properties of naturally occurring compounds,” Peter Liljeroth, co-author is the study, said in a media statement. “Our goal is to produce artificial designer materials that can be readily tuned and controlled externally to expand the range of exotic phenomena that can be realized in the lab.”

As an example, Liljeroth mentioned that heavy-fermion materials could act as topological superconductors, which could be useful for building qubits that are more robust to noise and perturbation from the environment, reducing error rates in quantum computers....