Two-Dimensional Magnetic Materials for the Next Generation of Functional Device Platforms (2DMagnete)

Magnetism is perhaps the oldest known physical phenomenon of entirely quantum mechanical origin. From the early studies performed by William Gilbert in his 1600 monograph De Magnete, through to current magnet hard-drive technology using spintronics concepts, several open questions still remain on the limit of magnetism at truly two-dimensional (2D) magnets. This is an intrinsic problem pointed out more than 70 years ago by pioneers in the field such as Louis Néel, Lev Landau or Lars Onsager but still without a plausible solution. Nowadays with the advent of different computational simulation techniques, and experimental approaches, we have the opportunity to tackle this cutting-edge problem with fundamental and technological implications in a real live-basis.

The 2017 breakthroughs in discovery of 2D magnetism in monolayer semiconductor crystals (e.g. CrI3) and observation of layer-dependent magnetic phases (e.g. antiferromagnetic or ferromagnetic) open up new paradigms in fundamental science and device technologies. These compounds have enormous potential for magneto-electronics, as well as combining logic and memory for high-performance computing. One game-changing idea is to develop integrated 2D-magnets into selected matrices as smart hybrids with tailored functionalities. Such lightweight materials will have transformative applications in electromagnetic interference shielding (e.g. reduce electromagnetic pollution), low-energy data storage (e.g. better hard-drives), and ultralow-power switching (e.g. smarter health monitoring sensors). Their atomically thin nature will also enable unprecedented manipulation of magnetic properties by non-magnetic means, such as via electric fields or mechanical strain. The van der Waals (vdW) nature of these magnets enables arbitrary design of heterojunctions and devices, without lattice-matching constraints, formed either between different magnets or between magnets and other 2D materials. According to Nobel laureate Andre K. Geim, "the choice of possible vdW structures is limited only by our imagination". Thus, the discovery of 2D magnets combined with interfacial engineering capabilities breaks new ground in the fundamentals of magnetism, with unprecedented control and new functionality.

In this project we will: (1) propose focused theory developments to elucidate the magnetic properties of intrinsic vdW materials to groundbreaking advances in device platforms. This is triggered by the ultimate question: "What is the limit of magnetism in an atomic layer material and how to manipulate it?" Long-searched but only recently discovered, truly 2D magnetic materials could enable a revolution on how information data is accessed, understood and stored. How they work is completely unknown. We aim to show how this phenomenon occurs and how to control it. Doing so would bridge the gap across different length scales at finite temperature of a radical new class of magnetic materials. This will lead to a scientific breakthrough in the understanding of low-dimensional magnets and their integration with optics and electronics in a cheap and feasible way in ultra-compact spintronics. (2) To do this we have three steps to take: i) to develop and apply high-throughput techniques to quantum mechanical simulations to predict the best materials that can be truly 2D magnets at temperatures of technological relevance; ii) to benchmark our modelling across different dimensionalities - atomistic (few Å's), mesoscopic (several nm's) and macroscopic (hundreds of micrometer's) - to bridge the modifications of the magnetic phenomena at 2D; and, finally, iii) to investigate the interplay between magnetic properties with external driving forces (electric/magnetic, strain, interfaces) to obtain magnetic control using multiscale methods. Technologically, our proposal would pave the way to materials design of 2D-magnets and goes well beyond the currently possible applications of data storage on magnetic device.

Knowledge:
The research outlined in this proposal will lead to the realization of synergies through the formation of a multidisciplinary data-driven approach to study the magnetic properties of van der Waals (vdW) layered materials to enable exciting scientific findings. We will investigate fundamental features such as thermal stability, degradation of properties in different environments (e.g. air moisture, substrates), effect of defects on the magnetic ordering, and assembly of vdW layers with different magnetic characteristics, using a plethora of compounds of different chemical formula. We will develop several analytical techniques based on general Heisenberg Hamiltonians including non-collinear effects (e.g. Dzyaloshinskii-Moriya interactions), carry out state-of-the art first-principles simulations and integrate these approaches in a multiscale framework. These theoretical efforts will be benchmarked by the Chhowalla group in the University of Cambridge. This will open novel pathways for the analysis and research of new materials and processes at the limit of very few atoms but still with possibilities for integration in advanced device platforms. The algorithms, software, workflows and scripts produced will be made publicly available. This material will be uploaded to the GitHub. The raw data will be uploaded to NOMAD repository, which is an open source database. This will help in a fast and freely dissemination of our results through the academic community.

Technological/Economic/Industry:
Truly 2D magnetic materials could enable a revolution on how information data is accessed, understood and stored. This research-driven innovation goes well beyond the currently possible applications of data storage on magnetic devices explored in industrial scales. It clearly sets new targets in terms of innovation policy, commercial developments and technological integration in widely used communication/information means. New products and procedures will be designed out of our research. This will help to increase the competitiveness of the UK economy in the creation of innovative, disruptive products and technologies based on novel materials. To accelerate the economic impact of our research, we will engage with the Department of Materials Science and Metallurgy at the University of Cambridge. In particular, this collaboration will create a critical mass of expertise on the industry-related developments in application of 2D magnets. My group will work closely with the Henry Royce Institute at Cambridge to successfully maximise impact, enable technology transfer and yield an achievable pathway to implement our findings in novel processes and goods.

General Public/Society:
One of the greatest opportunities and challenges facing policymakers today is the ever increasing significance of data. It is estimated that we produced roughly 2.5 Exabytes (2.5 billion gigabytes) everyday. This is equivalent to more than 18 million weather forecast requests, or 154,200 call per minute on Skype. Responding to the modern society's challenge of easier data access in cheaper devices (e.g. hard-drives) but at low-energy data storage is a priority in this Fellowship. Our proposal aims to make a significant leap forward to the solution of the increasing problem of the amount of data that is generated and stored daily either in the UK or globally. The benefits for the society are many, from revolutionising the information available at our fingertips with clever apps, reduce energy usage, up to new data-storage technologies which can change the way we see our surroundings. We will engage with the general public and communicate our research findings and their impact via several means. For instance, through presentations at high schools and science festivals, press releases and science podcasts in specialized portals and regular newspapers.