DMREF: Antiperovskite Interfaces for Materials Design

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NON-TECHNICAL DESCRIPTION: Materials with a particular crystalline arrangement of atoms, known as perovskite, have played important roles in applications ranging from electronic and magnetic devices to micro-machined actuators and sensors. Some of the most interesting phenomena arise at interfaces between these and other materials, where the atomic and structural aspects combine to form new materials in their own right. The main goal of this research is the discovery of a new class of interface materials based on antiperovskites. These antiperovskites exchange the atomic positions of the more common perovskites, creating unique, wide-ranging properties different from the parent materials. Interfaces between these two 'anti'-structures create unexplored fundamental opportunities for materials design. This research will discover the fundamental principles controlling these new materials systems, develop atomic-scale design principles, and create and explore these interfaces for potential applications in electronic, magnetic, and quantum-controlled devices. TECHNICAL DESCRIPTION: Complex perovskite materials have been fertile ground for new discoveries, due particularly to their wide-ranging structural, electronic, optical, and magnetic properties. Interfaces between perovskites create juxtapositions between different symmetries and ordered states, and it has become clear that these interfaces are new materials in their own right, with inherently multiple length-scale distortions near the interface that lead to rotations, deformations, and electronic and structural orderings dramatically different from those in bulk. The main goal of this research is the discovery of a new class of interface materials based on antiperovskites. Antiperovskites have the perovskite structure, but cation and anion positions are interchanged, resulting in unique, wide-ranging properties different from perovskites. Interfaces between these two 'anti'-structures create unexplored fundamental opportunities for materials design. The fundamental principles controlling new physical phenomena at these interfaces will be determined, and the principles used to design couplings between multiple orders at interfaces to generate new functionalities. This research is aimed at developing atomic scale design principles for antiperovskite heterointerfaces, constructing databases of the stable interface structures, and developing antiperovskite heterostructures with scientifically important and technologically transformative structural, electronic, and magnetic properties. The project implements an integrated effort of theory, materials synthesis, structural, electronic, and magnetic characterization. The research will use an iterative approach, where feedback from experimental measurements of interfacial structure and electric and magnetic order is used to refine theoretical parameters and approximations. This iterative approach will develop a fundamental understanding of the interface atomic structure and bonding between disparate materials, and how it creates new interfacial spin order and electronic configurations. These atomic-scale interface materials will lead to new classes of controllable electronic and magnetic phenomena, and new growth approaches that will make possible heteroepitaxy of other materials systems with large disparity in structure and chemical bonding. The predictive theory and modeling, with feedback to theory from materials growth, and from structural, electronic, and transport characterization, will produce hetero-interfaces that have unique properties not presently available.