Many modern technological advances are dependent upon either the development of new materials, or better control and understanding of existing materials. As materials' properties depend on their constituent nuclei and electrons, accurate modelling of their electronic structure is crucial. In principle, this should be straightforward, as the fundamental quantum mechanical equations governing their behaviour have been known for almost 100 years; however, solving these equations is extraordinarily hard. The key advance has been the development of high quality computer simulation methods for many-electron systems able to describe realistic materials, and the UK has been at the forefront of this new field since the very start. The UKCP HEC, focused on density functional theory methods, has played a fundamental part in this effort via both developing theories, software and algorithms, and exploiting these innovative tools in use cases relevant to a range of disciplines and industries. UKCP also supports experimental communities, via computational training, RSE time and computer allocations on Tier-1 and Tier-2 HPC. The close interaction between DFT theorists, software developers and users drives innovation and expands simulation capabilities, as well as magnifying the impact of the work. The research proposed does not easily fit traditional categories of "physics", "chemistry" etc; instead, UKCP is a multidisciplinary consortium using a common theoretical foundation to advance many areas of materials-based science, with the potential for significant impact both in the short and long-term. UKCP currently comprises 24 different nodes in physics, chemistry, materials science & engineering, with over 150 active researchers. Each node is a different University Department, represented by one key academic (a Co-I on the grant). This proposal provides computational support for a large body of research across UKCP (over £40M in already-awarded grants) with a substantial allocation of ARCHER2 and Tier-2 HPC resources plus Research Software Engineer (RSE) support. The RSE provides essential expert coding support for the principal UKCP codes (CASTEP, CONQUEST & ONETEP), develops new code features as required for some UKCP projects, and assists with training and supporting the UKCP codes' user-communities. The innovations in this proposal enable the next generation of simulations and further widen our computational horizons. UKCP will develop new algorithms, workflows & theoretical methods to increase our simulation abilities, in terms of both new functionality and dramatically improved accuracy & speed. New algorithms include embedding machine learning methods into DFT to speed up calculations, and enabling treatment of large systems (bringing together the CASTEP & ONETEP codes into a single workflow and enabling DFT codes to be embedded in multiscale, multiphysics simulations). GPU ports and improved parallelism enable UKCP software to exploit current and future HPC architectures effectively & with greater energy efficiency. New functionality includes NMR spectroscopy with spin-orbit coupling, so the full periodic table can be studied with high accuracy, and advances in excited state modelling, including temperature and environmental effects. These developments enable larger, more complex systems to be studied and will make significant impacts on many areas of future technology, including LED lighting, improved wear/corrosion resistance, next generation batteries, low power electronics & spintronics, improved energy-harvesting (thermoelectric) materials, new materials for carbon capture/storage and nanoparticles for water purification. There are also areas of fundamental research, to further our understanding of basic properties of matter, such as dynamics at molecule/metal interfaces, electron interactions in solid/liquid interfaces, quantum effects in biological processes, protein-ligand binding & high-pressure hydrogen phases

First-principles quantum-mechanical simulations based on density-functional theory (DFT), are today used hand in hand with experiment to design new materials. Conventional DFT has a computational effort which increases with the cube of the number of atoms and this limits the practical size of calculations. ONETEP is a world-leading UK-developed software package which uses a linear-scaling framework to enable calculations on much larger scales, uniquely without loss of accuracy compared to traditional methods. Thus ONETEP offers unmatched capabilities for constructing and simulating more realistic models of materials and including their environment in multiscale simulations. ONETEP has been developed from the beginning to take advantage of supercomputers. Due to its non-trivial formulation and wide-ranging functionality, it is a highly complex code consisting of around half a million lines of code. ONETEP is an academic community code which emerged from CCP9, the Collaborative Computational Project for the electronic structure of condensed matter, bringing together academics across disciplines, and forming the UK branch of the European Psi-k Network. In 2016 ONETEP became the flagship project of CCP9 and free to UK academics. Industrial exposure to ONETEP has resulted from close collaboration with BIOVIA, which has enabled integration with their Materials Studio user interface. This has led to considerable commercial impact and new industrial collaborations. Beyond the UK, ONETEP is gaining in popularity with developers in Ireland and China and users in many countries in Europe as well as the USA, China, Mexico and South Africa. As with all software, ONETEP needs to be continuously evolved and updated in order to stay at the cutting edge. This is particularly challenging for a large collaborative academic project that has evolved over two decades. Furthermore, a range of developments, such as excited states, electrochemistry, embedding and wavefunction methods, have required pervasive changes. Since they affect the core algorithms of the code, these changes have inevitably led to increased complexity. Thus the code now needs to adopt a new structure to ensure its continued growth. At the same time it is important to maintain and further widen the community of users and developers to fulfill its primary objective to cater for the needs of the scientific community. This project is targeted towards these two interconnected aims. It will re-engineer the code in its entirety, rationalising internal structure to allow further development and enhance the interoperability of existing functionality. Modern software engineering principles will be followed throughout, in close collaboration with the computational physics and chemistry groups of STFC SCD and research software engineers in Southampton, Warwick and Imperial. At the same time developments of new functionality to enable large-scale calculations of crystalline and semicrystalline materials will satisfy a demand in this area by many researchers, such as in the CCP9 and the solid state microscopy and spectroscopy communities at STFC Facilities. Workflow tools and coupling with the ChemShell QM/MM code will be developed to allow adoption of the code by the biomolecular simulations community. The code will also be ported to emerging supercomputing architectures with GPU accelerators. Thus the project will support the rapidly-expanding communities within solid-state materials and biochemistry that deploy first-principles quantum simulations based on DFT. The project will deliver significant communication, engagement, and expert training and mentoring of new users to overcome initial barriers to access and enable them to use the code to make impact in their diverse research areas. Training events for both users and developers of the code will be embedded within each community.

The challenge we have set ourselves is to find fundamentally new ways to store, manipulate and transport information based on our unique approach to materials integration and interface control. Electronic applications and their use are increasing at exponential rates with 6% of the global energy consumed by ICT. As anyone who has used an electronic gadget knows, they rapidly get warm. But the heat is a by-product of the way that they use electric currents which is unsustainably dumped into the environment. Electric currents are used to transfer information, to store it, retrieve it and to perform operations. As devices become smaller, the problem increases because the materials become more resistive to currents and generate more heat. The scale of the problem is huge. As an example, Google reports that significant amounts of energy are used to cool their server farms. In 2021, they used ~12 TWhr of electricity, about the same as a small country, and the trend is increasing. The internet currently has a carbon footprint that is larger than that of the airline industry and is predicted to double from 2020 to 2025. For long-term sustainability we must reduce the consumption of energy in ICT. Spintronics exploits the magnetic property of electrons (spin) for applications. It offers compelling possibilities for new devices that might function at reduced energy. Pure spin currents transfer spin without transferring charge so that information can be exchanged without the heat a charge current generates. Using electric fields in devices can have great advantages over magnetic fields, including using less energy, but usually magnetism cannot be controlled by electric fields. Molecular interfaces can be altered by electric fields and ferroelectrics have a polarisation that can be switched electrically hence tuning the behaviour of a magnet when they are connected. A stumbling block to progress is that these different materials require different techniques of preparation and to be useful in ICT they must be thin - of the order of tens of atoms thick. Such thin layers need to be protected during their fabrication and then the different layers combined. The solution requires bespoke designs and breakthroughs in materials science. The Royce Institute is a key EPSRC investment (£235M) founded to "accelerate the invention and take-up of new material systems that will meet global challenges", driving the UK strategy to increase our ability to compete, not only in science, but in the marketplace. At Leeds we recently installed the Royce Deposition System: a £2.2M suite of chambers each of which is designed to grow a different type of advanced material that requires different deposition methods and environments for processing. The chambers are connected together through ultra-high vacuum tubes so samples can be transferred whilst being protected from the atmosphere and impurities. Crucially, by controlling their interfaces at the atomic level we can grow layers of different materials and bring them together into a single hybrid structure. For example, we can: form 2 dimensional materials with electrical polarisation to control magnets; build molecular thin film interfaces that lead to tuneable emergent magnetic, optoelectronic and superconducting properties; drive magnetic textures using spin currents from topological materials, etc. A complete understanding of these hybrid structures will pave the way to exploitable technology where the initial benefits will enable information processing and storage with less energy, reducing carbon emissions and prolonging battery life. Our approach has the potential to impact many areas of technology such as data storage, sensors, energy storage, and quantum materials.

Molecular modelling has established itself as a powerful predictive tool for a large range of materials and phenomena whose intrinsic multiscale nature requires modelling tools able to capture their chemical, morphological and structural complexity. In the UK, the molecular modelling community, supported by the software, training and networking activities coordinated by the CCP5, has become, over the past 40 years, international-leading in this field. Building upon these successes, the new CCP5++ network will revolutionise the field of materials molecular modelling creating a new integrated community of modellers, experimentalists and data scientists that together will identify the new frontiers of the field and will transform the way these disciplines work together. To achieve its mission, the CCP5++ will coordinate and support an ambitious plan of meetings, sandpits, coding workshops, secondments and visitor schemes to cater for the large community of modellers, experimentalists and data scientists working on advanced materials. This support has proved to be vital to enable the UK condensed matter community to attain and maintain an international position at the forefront of such an intensely competitive field and will enable the UK researchers to identify and tackle major world challenges in-silico materials discovery. From the start the network memberships include key representatives of the experimental and data science communities, international software and modelling institutes, industrial collaborators and national HPC consortia and CCPs, that working together will shape the future of materials molecular modelling.