Discovery and Fundamental Investigation of Emergent Phenomena in Novel 2D Magnets

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Nontechnical Abstract:Magnetic materials have long been recognized for their technological importance, beginning with the compass, and are an integral part of today’s information storage and many other standard applications. However, such applications demand new magnetic materials with new properties. The recently discovered two-dimensional (2D) magnetic materials pose an immense advantage in this regard and offer a unique set of properties that are not possible with the existing magnetic materials. They measure only a few atoms in thickness, they are flexible, and better yet they can be stacked onto each other -much like Lego bricks- to form entirely new materials with new magnetic properties. The goal of this research program is to expand the library of 2D magnets employing a combination of experimental and theoretical methods. The outcome from this project benefits society by offering new magnetic materials for potential applications in data storage, quantum communication, and consumer electronics fields. The proposed multidisciplinary research program also provides an excellent training platform for undergraduate and graduate students, involves K-12 students in active research environment through the Arizona State University SCENE program, and will enable the development of new modules for existing undergraduate and graduate level courses. Technical Abstract: Two-dimensional (2D) van der Waals magnets offer unique opportunities from a fundamental as well as a technological perspective. While the first 2D material graphene was discovered back in 2004, it took more than a decade to show experimental evidence of long-range magnetic order in 2D. To date, magnetic order in 2D has been demonstrated only in a handful of materials and Curie temperatures (Tc) remain lower than 300K which is an important consideration for their disruptive impact in applications. This proposal combines advanced theoretical and experimental techniques to predict, synthesize, characterize, and manipulate the properties of entirely new-classes of 2D magnetic materials: from ferromagnetic insulators, to ferromagnetic half-metals, antiferromagnetic chiral higher order topological insulators and quantum anomalous Hall effect insulators. If successful, these studies will lay a solid foundation to create novel 2D magnets, combine topological order with magnetism in 2D, and take aggressive steps towards demonstrating the first chiral higher order topological insulators while significantly advancing our understanding of magnetism in the 2D to 3D crossover limit, and the effects of pressure, gating, and chemical substitution.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.