Physicists at MIT and their collaborators have stumbled upon a novel method to produce a state of matter called a strange metal, known for its peculiar physics and its presence in high-temperature superconductors critical to various applications.
This breakthrough offers a fresh approach to crafting and studying strange metals, whose electron behavior diverges from that of conventional metals like copper.
Joseph G. Checkelsky, the lead researcher, expressed enthusiasm about the discovery’s potential, stating, “It is a potential new approach to designing these unusual materials.”
The team believes that this innovative approach to creating strange metals will aid in formulating a unified theory to explain their behavior. “This has been quite challenging to date, and could lead to a better understanding of other materials, including high-temperature superconductors,” remarked Linda Ye, the study’s first author.
The journey to this discovery began in 2018 when Checkelsky and his team explored a class of quantum materials known as kagome metals. These metals feature atomic layers arranged in a lattice reminiscent of a Star of David or sheriff’s badge, with the pattern also prevalent in Japanese culture.
“We were interested in the Kagome lattice because theory showed that it should host a variety of interesting features for electrons sitting on it,” Ye explained.
Their initial findings in 2018 revealed that the Kagome metal produced Dirac fermions, nearly massless particles akin to photons carrying light. However, the recent discovery of strange metals within the same lattice was entirely unexpected, ushering the researchers into uncharted territory.
Following the discovery of Dirac fermions, the team sought to uncover even more intriguing phenomena, particularly the existence of a flat band within the Kagome lattice. This phenomenon, akin to electrons standing still while still spinning on their axes, facilitates electron interaction, leading to intriguing behaviors in condensed matter physics.
Their exploration revealed a flat band at the Fermi level, akin to the ocean’s surface, and the subsequent examination under high pressure and magnetic fields unveiled the strong interaction between electrons within the flat band and others in the system. This interaction transformed the calm sea of unperturbed electrons into a turbulent storm, giving rise to the emergence of a strange metal.
According to Ye, the findings underscore the significance of the kagome lattice as a crucial design principle for generating novel electronic states. Moving forward, the team aims to expand their research to explore other lattice structures.
