Understanding the order and disorder in nature helps us make sense of it all. Animals fit neatly into categories, and so do materials, depending on the interplay of electrons, atoms, and their environments. Unlike animals, the boundaries of materials are less defined, and changes to their surroundings can cause them to move between categories. Different phases can emerge within a single category, resulting in unexpected behaviors.
Scientists have used advanced imaging tools to visualize the nanoscopic universe of materials, uncovering surprising and unexpected phenomena. Recently, researchers from the University of Illinois, the University of Maryland, WashU, and the National Institute of Standards and Technology have observed unusual waves of charge within a crystal of uranium ditelluride (UTe2). This crystal exhibits unique superconductivity properties, and the researchers developed a model to explain the experimental observations.
Superconductors, materials that can conduct electricity without resistance, are still not fully understood. UTe2 is one such superconductor that has been the focus of recent research. At ambient temperatures, UTe2 appears unremarkable, but as it is cooled with liquid helium, it exhibits superconductivity.
Unlike regular conductivity, which involves the movement of individual electrons, superconductivity involves Cooper pairs, where electrons interact with each other. UTe2 exhibits a rare form of superconductivity called triplet pairing. Using a scanning tunneling microscope, researchers were able to visualize the microscopic structure of UTe2 and discovered the existence of charge density waves in the superconducting state. These waves were found to be intertwined with the material’s superconductivity.
Further analysis revealed that the charge density waves were related to a wave formed by Cooper pairs within the material. These waves provide insights into the different types of order present in UTe2. Similar intertwined waves have been observed in other superconductors containing copper and oxygen atoms, but this is the first time they have been seen in a superconductor with triplet pairing.
This discovery adds to our understanding of the complex behavior of materials and opens up new possibilities for studying superconductivity.