The study has been publish in the journal Nature Communications and shows that it is possible to fabricate artificial materials, one by one, to produce electronic and magnetic properties that do not exist in any material found in nature. In this case, the scientists observed that conventional electrons in a metal becomes heavy electrons (the technical denomination is heavy fermions) in the proximity of ordered atomic structures of magnetic atoms (cobalt) arranged over the surface. Heavy fermions are electronic states that appear when normal electrons, which are intrinsically magnetic, are attracted towards the structure of magnetic atoms periodically arranged.
The researchers employed a Scanning Tunnelling Microscope at low temperatures to study the shape of this electronic states and demonstrate that they correspond to the emergence of a heavy fermion state. This is te first time that te formation of such novel state of matter is monitored by constructing the artificial material one atom at a time. “We found that the magnetic fingerprint of this electrons extended delocalized along a magnetic chain of up to 20 cobalt atoms, allowing us to demonstrate that they correspond to a new electronic state of matter, and provide a theoretical model for creation of heavy electrons that could be extended to other systems, thus boosting the search of artificial materials with novel functional properties.” Explains David Serrate, scientists in ICMA and leader of this study.
The exotic electronic and magnetic properties of this materials cause great expectations in their possible use for applications such a sensors, superconducting devices or to explore critical quantum proceses. Heavy electrons behave drastically different than normal electrons, because their response to temperature, pressure of magnetic fields scales with the mass of the electrons. Additionally, the observation of these novel states inspire new theoretical models that allows us to explore the quantum limits of matter and design new artificial materials with customized electronic behaviour.
The meeting marks the starting point of a 4-year research project that is coordinated by CIC nanoGUNE and integrates IBM Research, Donostia International Physics Center, and University of Santiago de Compostela, Technical University of Delft and the University of Oxford. The consortium of these 6 leading European research institutions has been granted a total of €3.5 million from the European Commission under the highly competitive Horizon 2020 FET-Open call, which funds cutting-edge high-risk / high-impact interdisciplinary research projects that must lay the foundations for radically new future technologies.
The SPRING project combines recent scientific breakthroughs from the consortium members to fabricate custom-crafted magnetic graphene nanostructures and test their potential as basic elements in quantum spintronic devices. The targeted long-term vision is the development of an all-graphene – environmentally friendly – platform where spins can be used for transporting, storing and processing information.
The spin is an intrinsic property of electrons that makes them behave like tiny magnets. For instance, every electron in any material carries both a charge and a spin, the latter playing a key role in magnetism.
Within the scientific community there is consensus that spin is the ideal property of matter to expand the performance of current charge-based nanoelectronics into a class of faster and more power-efficient components, being the basis for the emerging technology called quantum spintronics. The SPRING project will investigate the fundamental laws for creating and detecting spins in graphene, this is to read and write spins, and using them to transmit information.
Jose Ignacio Pascual, Ikerbasque Research Professor at CIC nanoGUNE and scientific coordinator of the project, explains that “graphene is ideal to host spins and to transport them. This atomically thin material can now be fabricated with atomic precision, opening the door to fabrication of designer structures with precise shape, composition, spin arrangement, and interconnected by graphene electrodes for electrostatic or quantum gates. The potential is a platform for the second quantum revolution as qubit elements for quantum computation.”