Research Rai Maciel de Menezes

Abstract

Modern Artificial Intelligence (AI) relies on artificial neural networks, which attempt to emulate the functionalities of the human brain through a set of highly interconnected nodes that play the role of artificial neurons, and may revolutionize the way we interact with technology. Currently, the most robust artificial neural networks are constructed using appropriate software models on CMOS hardware. However, how calculations are carried out on computers differs significantly from how the brain processes information. The prominent modern alternative are the wave-based physical systems. They have been recently demonstrated to operate as recurrent neural networks, where interference patterns in the propagating waves can realize an all-to-all interconnection between points of the host medium, exploiting the rich nonlinear dynamics that mimics the action of artificial neurons by scattering and recombining input waves in order to extract the carried information. Especially spin-waves (magnons) in magnetic films are promising candidates for practical applications due to their low power usage, strong nonlinearity arising from magnetization dynamics, and established scalability as well as integrability of magnetic nanostructures. Spin waves are readily employed for performing logic operations and recent advances have been made towards magnonic artificial intelligence, where different types of nanoengineered magnon scattering reservoirs have been explored. However, realizing the full potential of these ideas requires precise manipulation of spin waves in nanostructures, which is still a challenge and needs to be promptly advanced for the benefit of functional magnonic devices. In this project, we put forward magnonics in rapidly emerging 2D magnetic materials as a viable platform for neuromorphic and reservoir-computing applications. The magnetic properties of these atomically-thin, crystalline materials are extremely prone to electro-mechanical tuning, such as by lattice straining, gating, defect engineering, and/or layer stacking and heterostructuring. Furthermore, the recent observations of high-frequency (THz) spin-wave modes in monolayer CrI3 and room-temperature 2D ferromagnetism in several other materials put all the ingredients in place for the use of 2D magnetic materials as a technological platform for spin-wave-based neuromorphic computing. That said, theoretical and simulation insights are critically lacking in this field, which we aim to timely rectify in the present proposal. We will devise strategies to broadly and actively tune magnonic excitations and their propagation in selected 2D materials by nanoengineered structural and electronic stimuli, and engage to map out the viable realizations of neuromorphic computing in such materials, for which we will provide detailed theoretical recipes and in silico demonstrations. Considering that crystalline 2D materials offer a closest possible connection between the simulation environment and the practically measured quantities, our discoveries are bound to inspire experimental replication and further advances of magnonic technology.

Researcher(s)

• Promoter: Milosevic Milorad
• Co-promoter: Maciel de Menezes Rai
• Fellow: Oliveira da Silva Jean Felipe

Research team(s)

• Condensed Matter Theory

Project type(s)

• Research Project

Abstract

Magnetic skyrmions, the nanoscale topologically swirling spin-textures, hold promise as information carriers for the next generation of low-power spintronic devices. On that path, enhancing their density, stability, and facilitating their creation, manipulation and detection are the key challenges. The recent discovery of intrinsic magnetism in two-dimensional (2D) van der Waals (vdW) materials has radically raised the expectations towards skyrmionic applications. The established ability to broadly tune properties of 2D materials by straining, gating, heterostructuring, makes them an ideal platform for controlling emergent magnetic phases, including skyrmionic ones. The latest experimental observation of ferromagnetic skyrmions in some vdW heterostructures strongly boosted the need for a skyrmionics roadmap in 2D materials that only theoretical simulations can provide, and that is the prime objective of this project. This goal requires developing an advanced multiscale methodology able to account for the manipulations by design in vdW systems, understanding the physics down to the very source of competing magnetic interactions, and detailing the magnetic phase diagrams of 2D materials as a function of mechanical, structural and electronic degrees of freedom, as well as the applied magnetic field and current. Our roadmap will also include the highly sought antiferromagnetic skyrmions, which will definitely promote skyrmionics in 2D materials to the technological paragon level.

Researcher(s)

• Promoter: Milosevic Milorad
• Fellow: Maciel de Menezes Rai

Research team(s)

• Condensed Matter Theory

Project type(s)

• Research Project

Abstract

Precise control of the magnetic phases of matter has revolutionized technology in recent decades. The discovery of novel magnetic materials has radically raised the expectations towards ultra-fast yet low-power-consumption spintronic applications. Especially, numerical simulations of magnetic materials have played an indisputable role in predicting and understanding non-trivial magnetic states for applications. However, although different numerical approaches are readily verified to accurately represent the magnetic behavior in different scenarios, a complete description of magnetic phases often requires a laborious connection between numerous simulation packages which operate at different time and length scales. In this project, we collaborate with key specialists to develop an open-source integrated multiscale framework for state-of-the-art magnetic simulations, from first principles to micromagnetic regimes. This will require advancing a precise interconnection between different (pre-existing) numerical approaches to accurately describe magnetic phases at different time and length scales, bringing magnetic simulations to an unprecedented and extremely versatile level.

Researcher(s)

• Promoter: Maciel de Menezes Rai

Research team(s)

• Condensed Matter Theory

Project type(s)

• Research Project

Abstract

Through this DOCPRO1 project, the PhD student will finalize his thesis on heterochiral magnetic films, based on the just developed generalized Heisenberg methodology on an arbitrary lattice, enabling him to broadly explore the magnetic phase diagram of mono- and bi-layer spin-lattice systems with spatially nonuniform chirality. This study is motivated by recently discovered 2D magnetic materials, their lattice structure, anisotropy, emergent chirality, and geometrical manipulations known to van der Waals engineering. Besides the generic topological characterization and classification of the possible spin textures, attention will be paid to the emergent spin-wave (magnonic) properties in the given spin landscape and novel concepts for spintronic devices.

Researcher(s)

• Promoter: Milosevic Milorad
• Fellow: Maciel de Menezes Rai

Research team(s)

• Condensed Matter Theory

Project website

Project type(s)

• Research Project