An international team of physicists has “stumbled upon” an entirely new material, which they have called “Weyl-Kondo semimetal”. The “semimetal” belongs to a category of substances known as “quantum materials”. The word quantum in ‘quantum materials’ means they have properties that cannot be described by classical physics and thus we have to invoke quantum physics.
For the time being, however, researchers working on quantum materials are trying to understand how they work and how more useful ones can be produced.
“The word quantum in ‘quantum materials’ means they have properties that cannot be described by classical physics and thus we have to invoke quantum physics,” said Dr Amalia Coldea, a quantum materials researcher at the University of Oxford who was not involved in this new study.
“Often we refer to materials where there are very strong interactions between their components – you don’t know what properties they will have, and you can’t predict in advance.”
As scientists don’t necessarily have the theories to predict the behaviour of quantum materials, often they create them experimentally first and measure them to observe their properties.
The new material presented in PNAS emerged this way. Scientists had the material (Vienna, Austria) and the theory (Rice University, Texas) developing in parallel.
Prof Buehler-Paschen and her team experimented with structures made from the metals cerium, bismuth and palladium in very specific combinations.
This work then fed into theoretical work being done by Dr Hsin-Hua Lai and his team at Rice University, who realised the potential to create an entirely new material.
“We really just stumbled upon a model in which, suddenly, we found that the mass had gone from like 1,000 times the mass of an electron to zero,” said Dr Lai.
The scientists realised that these particles were originating due to a phenomenon known as the “Kondo effect”, leading them to name their new material Weyl-Kondo semimetal.
Currently we design these materials to find new effects. We search for them because these effects could be very useful, with technological applications like quantum computing.