Grant: Discovery Grants Program - Individual

The rapid growth of digital technology, which is forecasted to result in information and communications technology consuming 20% of the world's electricity by 2025, is fuelling efforts to find more sustainable ways of computing. Topological materials are poised to play an important role in addressing this challenge. The term topological derives from the field of mathematics that studies how shapes can be continuously deformed into one another. These materials naturally form localized objects that are particularly resilient to destruction by external influence, which makes them well suited to be carriers of information in the next generation of computer architectures. This proposal brings together two classes of topological materials. In one class, the topological objects are nanoscale swirls in the magnetic orientation of the atoms called skyrmions. Skyrmions are high-density, non-volatile, information carriers that can be pushed through wires with an energy cost that is that is far smaller than required to move other magnetic structures. As a result, they are being considered for application in neuromorphic computers consisting of networks of interconnected nodes that contain skyrmions. These architectures would provide artificial intelligence at a fraction of the energy cost of conventional computers. The second class of materials are topological metals. Most of the work to date on topological metals is on bulk materials, while relatively few examples exist in thin film form. Topological metals have many unique and interesting electronic features in their own right, but they can also serve as precursor states that can be tuned by external influence to access additional topological states. Strain and film thickness are two parameter that we will explore that can give rise to transitions in the topological states. We will explore topological thin films down to the atomic limit, where confinement of the electronic states can transition the material into a novel state that is insulating in the interior of the film, but where its edges conduct electricity with very little loss in energy. The edge states can exhibit exotic quantum mechanical properties with potential applications in quantum computing. We will explore what happens when we layer different thin film topological metals together which can turn on large effective magnetic fields inside the materials that have large impacts on their transport properties. As the states in the topological metal have been demonstrated to be manipulated with external magnetic fields, we will then form hybrid structures by layering skyrmion and topological metals films to explore how the localized magnetic field emanating from the skyrmions are able to generate novel localized topological objects in the adjacent layer. These states could then be shuttled by controlling the skyrmions as a new means of quantum control for the next generation of quantum devices.