NSF Award
2429994
Collaborative Research: ENG-SEMICON: Integrating Magneto-ionic and Ferroelectric Control of 2D Magnets for Energy-efficient Skyrmion-based Memory<br/><br/>Non-technical abstract:<br/>Magnetic materials are widely used in today’s society. In conventional magnetic materials, their magnetic moments prefer to line up in a parallel fashion. In certain special magnetic materials, their moments wind up into a twisting pattern named “magnetic skyrmions”, which contain topological characters. Such magnetic skyrmions are considered as potentially robust information carriers for the development of novel memory devices for data storage and computing. Hence, low-voltage control of magnetic skyrmions becomes a scientifically intriguing and technologically relevant topic. This project aims to build low-power skyrmion memory based on the studies of the effects of adjacent materials such as ionic materials and ferroelectric materials on atomically thin magnets such as two-dimensional van der Waals magnets. When a small voltage is applied to either mobilize the ions or switch the ferroelectric polarization, properties of the neighboring magnets will be altered, potentially leading to the energy efficient control of magnetic skyrmions in two-dimensional magnets. When the ionic materials and ferroelectric materials are stacked together, the synergy of these two materials may enable new types of energy-efficient skyrmion memory. Graduate, undergraduate, and high-school intern students, from all backgrounds, are trained with a rich set of expertise in two-dimensional materials preparation, thin film deposition, nanoscale device fabrication, and a variety of optical and electron-beam microscopies and spectroscopies. This project can help prepare the future workforce for the semiconductor device science and technologies in the U.S. and raise the public literacy of microelectronics by new course development and local educational activities.<br/>Technical abstract:<br/>Magnetic skyrmions are topological spin textures that have been envisioned to circumvent local defects, in contrast to domain walls that are more susceptible to defect pinning, for efficient and reliable information storage and transmission. Creation and manipulation of skyrmions in ultrathin material platforms may enable energy-efficient ultracompact spintronic devices. However, traditional magnetic thin films inevitably contain defects and structural nonuniformities, hindering the development of high-performance skyrmionic devices. In stark contrast, the emergent two-dimensional van der Waals magnets exhibit single crystallinity with minimal defects, holding unique promise for exquisite control of skyrmions towards practical devices. This project aims at achieving energy-efficient skyrmion-based memory by creating, manipulating, and annihilating skyrmions in two-dimensional van der Waals magnets using magneto-ionic and ferroelectric means. First, a magneto-ionic gate will be used to locally tailor the Dzyaloshinsky-Moriya interaction and magnetic anisotropy in magnets through ionic migration. Second, heterojunctions of ferroelectrics and two-dimensional magnets will be implemented to globally engineer the atomically thin magnets for skyrmion control through polarization-tunable Dzyaloshinsky-Moriya interaction and magnetic anisotropy. Third, the magneto-ionic and ferroelectric control will be integrated onto van der Waals magnets so that (1) the electric field effect in ionic layers can be amplified by ferroelectrics, (2) the ferroelectric coercivity can be lowered by ion-modulated domain wall nucleation, and (3) as a result, the voltage controlling efficiency of skyrmions can be largely enhanced, potentially enabling low threshold voltage switching of the skyrmion phases for non-volatile memory with ultralow energy consumption. This project will have broad impacts on the understanding of magnetic skyrmions in low-dimensional systems and the development of unconventional, energy-efficient memory devices, and will serve to prepare the workforce with expertise in energy-efficient nanoelectronic devices for the microelectronics industry in the U.S.<br/><br/>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.
