Electron Spin Effects in Semiconductor Nanostructure: Magnetism and Topology

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

Non Technical Abstract: This project involves investigating the connection between the science of magnetism and topology, which has recently become a major research frontier of semiconductor physics as well as quantum mechanics. The design and synthesis of quantum materials exhibiting this connection is, however, a major challenge. The specific goal of this project is therefore to design and synthesize new resilient materials in which this connection can be studied, and to achieve transformative discoveries using those materials. Those discoveries could result in new science and technology of interest in the emerging field of quantum computing. The project will use molecular beam epitaxy, which is a tool by which materials can be constructed atom-by-atom. This allows the design of materials with new functionalities that can be utilized in contemporary and emerging technologies. This research team will synthesize high-quality semiconductor materials with controllable magnetic properties. Another part of the project will include investigating the properties of semiconductor materials which have been stacked in periodic structures. The coupling between the different layers could lead to completely different functionalities not possible from either material separately. The project could potentially provide important solutions to next-generation devices for quantum computing and data storage devices that consume very low energy. This project will also train students by providing them with a skill set necessary to supply the nation's workforce to support and advance new technologies of quantum computing and data storage. Technical Abstract: The project involves the interplay between magnetism and topology in semiconductors, a combination of disciplines that has already delivered exciting discoveries which directly impact quantum and spintronic device physics. The specific goals of this project are to utilize tuning knobs, such as strain, heterostructuring and metastable phase synthesis, made possible by precision molecular beam epitaxy, aimed at developing robust spintronic topological phases. The proposed goals are reached by tackling two objectives. The first objective aims to harness perpendicular magnetic anisotropy in two-dimensional III-Mn-V interfaces to achieve a temperature-resilient quantum anomalous Hall effect. The second objective aims to engineer new emergent quantum phases of matter in magnetic topological superlattices consisting of stacks of topological and normal insulators, one of which is magnetic. By combining complementary expertise in material development, optical probes, and electronic characterization tools, the team has the ability to achieve major breakthroughs toward advancing current understanding of magnetic topological phases and toward strengthening their resilience to environmental perturbations. The project synergizes those research objectives with a strong educational component that includes direct training by research on a variety of tools relevant to semiconductor and quantum technologies, and launching a course focused on topological phases in condensed matter physics. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.