Physicists from MYTH, working with other researchers, recently discovered a new method for creating a state of matter known as an unusual metal. The discovery, made by manipulating a quantum material characterized by atoms arranged in the shape of a sheriff’s star, could pave the way for advances in the field of high-temperature superconductors.
Strange metals and their importance
Strange metals attract special interest because of their unusual physics. Unlike conventional metals like copper, the electrons in strange metals behave differently, making them key to understanding high-temperature superconductors.
Joseph G. Checkelsky, principal investigator of this study and associate professor of physics, explains: “ This is a potentially new approach to designing these unusual materials. »
Linda Ye, first author of the article published in the journal Nature Physics, emphasizes the importance of this discovery: “ A new way of creating strange metals will help us develop a unique theory about their behavior. This has so far been very difficult and could lead to a better understanding of other materials, including high-temperature superconductors. »
Kagome metals
In 2018, Checkelsky and colleagues reported work on a class of quantum materials known as kagome metals. These material they consist of layers of atoms arranged in a series of repeating patterns, similar to a Star of David or a sheriff’s badge.
Linda Ye explains: “ We were interested in the Kagome lattice because theory showed that it should contain various interesting features for the electrons found there. »
In their 2018 paper, Ye, Checkelsky and their colleagues reported that their new metal Kagome produced Dirac fermions, nearly massless particles similar to photons that carry light.
You are looking for a straight line
The researchers then tried to discover an even more interesting feature in the Kagome network, called the flat band. This band allows the electrons to remain almost stationary, although they are still spinning on their own axis.
By investigating the electrical properties of the system under high pressure and magnetic field, they found that electrons in the flat band interact strongly with other electrons in the system, creating strange metal.
Linda Ye compares this phenomenon to a calm sea that becomes a stormy storm when electrons start interacting with each other. “ We knew that a flat strip would result in something interesting, but we didn’t know exactly what. And what we found was a strange metal, ” she says.
The discovery, published in the journal Nature Physics, is the result of several years of research. Linda Ye began researching the Kagome systems around 2015. This was a long project, ” she says. ” It is very rewarding to build this step by step and find a lot of interesting things along the way. »
Illustration title: Sketch of the electronic interactions within the kagomé network that lead to the strange metal. Credit: Paul Neves
Article: “A strange way to get an unusual metal” – DOI: https://www.nature.com/articles/s41567-024-02416-0