An important property of materials in the quantum state is now understood: the “curvature” of the space in which the electrons move. The research, published in Nature Physics, was conducted at Sincrotrone Elettra in Trieste and is the work of an international team involving Italian institutions CNR-IOM, the University of Bologna, the Ca’ Foscari University of Venice and the La Statale University of Milan
Research published in the journal Nature Physics presents a new method for greater understanding of quantum materials.
Employing an experimental technique using the synchrotron light source, an international team of researchers – including Italian organisations, the IOM Materials Foundry of the National Research Council of Trieste (CNR-IOM), University of Bologna, Ca’ Foscari University of Venice and La Statale University of Milan – have succeeded in measuring the “winding” of electrons, a property that determines certain particular characteristics of materials, knowledge which will be essential for their possible use in future advanced applications.
The study, conducted at Sincrotrone Elettra in Trieste, also involved academics from the University of Würzburg (Germany), the University of St. Andrews (UK), Boston College (US) and the University of Santa Barbara (US).
“The quantum properties of materials determine the behaviour of electrons, including their ‘topological winding’, meaning the curvature of the space in which they move within matter,” explains Ivana Vobornik, a researcher at CNR-IOM in Trieste. “By studying this property, one can identify the quantum properties of a certain material, and this enables greater understanding for applications in various technological fields, from renewable energy to biomedicine, and from electronics to quantum computers.”
Specifically, the team focused on a class of materials known as “kagome materials”, named for their close resemblance to woven bamboo threads in traditional Japanese baskets. “These materials are revolutionising quantum physics due to their magnetic, topological and superconducting properties. Understanding these properties is therefore key,” adds the researcher. “To measure the characteristic of electron winding, an experimental technique was employed that relies on a synchrotron light source. In this case, measurements were conducted at Elettra Sincrotrone Trieste. Synergy with theoretical analysis and the use of powerful supercomputers was also key: theoretical simulations made it possible to guide the experiments to the specific area of the material in which the properties being studied manifest”.
Rome, 12 June 2023
Image caption: Three perspectives of the surface on which electrons move, the Fermi surface. Left, the experimental result; centre and right, theoretical modelling. The colours red and blue represent a measure of electron speed. Both theory and experiment reflect the symmetry of the crystal, present in the Japanese “kagome” weave used to make traditional baskets.
Summary
Who: IOM Materials Foundry of the National Research Council of Trieste (CNR-IOM), University of Bologna, Ca’ Foscari University of Venice and La Statale University of Milan, University of Würzburg (Germany), University of St. Andrews (UK), Boston College (US) and the University of Santa Barbara (US).
What: “Flat band separation and robust spin Berry curvature in bilayer kagome metals”, Nature Physics (2023), DOI 10.1038/s41567-023-02053-z., link: https://www.nature.com/articles/s41567-023-02053-z
For information: Flavia Mancini, CNR-IOM, email: mancini@iom.cnr.it, mob.: +39 328 1230247, Giancarlo Panaccione, CNR-IOM, panaccione@iom.cnr.it, mob.: +39 335 5368898, Ivana Vobornik, CNR-Iom: vobornik@iom.cnr.it, mob.: +39 339 3967854 (contact details for professional use not to be published).