The Industrial Doctorate Centre in Molecular Modelling and Materials Science (M3S) at University College London (UCL) trains researchers in materials science and simulation of industrially important applications. As structural and physico-chemical processes at the molecular level largely determine the macroscopic properties of any material, quantitative research into this nano-scale behaviour is crucially important to the design and engineering of complex functional materials. The M3S IDC is a highly multi-disciplinary 4-year EngD programme, which works in partnership with a large base of industrial sponsors on a variety of projects ranging from catalysis to thin film technology, electronics, software engineering and bio-physics research. The four main research themes within the Centre are 1) Energy Materials and Catalysis; 2) Information Technology and Software Engineering; 3) Nano-engineering for Smart Materials; and 4) Pharmaceuticals and Bio-medical Engineering. These areas of research align perfectly with EPSRC's mission programmes: Energy, the Digital Economy, and Nanoscience through Engineering to Application. In addition, per definition an industrial doctorate centre is important to EPSRC's priority areas of Securing the Future Supply of People and Towards Better Exploitation. Students at the M3S IDC follow a tailor-made taught programme of specialist technical courses, as well as professionally accredited project management courses and transferable skills training, which ensures that whatever their first degree, on completion all students will have obtained thorough technical and managerial schooling as well as a doctoral research degree. The EngD research is industry-led and of comparable high quality and innovation as the more established PhD research degree. However, as the EngD students spend approximately 70% of their time on site with the industrial sponsor, they also gain first hand experience of the demanding research environment of a successful, competitive industry. Industrial partners who have taken up the opportunity during the first phase of the EngD programme to add an EngD researcher to their R&D teams include Johnson Matthey, Pilkington Glass, Exxon Mobil, Silicon Graphics, Accelrys and STS, while new companies are added to the pool of sponsors each year. Materials research in UCL is particularly well developed, with a thriving Centre for Materials Research and a newly established Materials Chemistry Centre. In addition, the Bloomsbury campus has perhaps the largest concentration of computational materials scientists in the UK, if not the world. Although affiliated to different UCL departments, all computational materials researchers are members of the UCL Materials Simulation Laboratory, which is active in advancing the development of common computational methodologies and encouraging collaborative research between the members. As such, UCL has a large team of well over a hundred research-active academic staff available to supervise research projects, ensuring that all industrial partners will be able to team up with an academic in a relevant research field to form the supervisory team to work with the EngD student. The success of the existing M3S Industrial Doctorate Centre and the obvious potential to widen its research remit and industrial partnerships into new, topical materials science areas, which are at the heart of EPSRC's strategic funding priorities for the near future, has led to this proposal for the funding of 5 annual cohorts of ten EngD students in the new phase of the Centre from 2009.

The Centre for Doctoral Training in "Molecular Modelling and Materials Science" (M3S CDT) at University College London (UCL) will deliver to its students a comprehensive and integrated training programme in computational and experimental materials science to produce skilled researchers with experience and appreciation of industrially important applications. As structural and physico-chemical processes at the molecular level largely determine the macroscopic properties of any material, quantitative research into this nano-scale behaviour is crucially important to the design and engineering of complex functional materials. The M3S CDT offers a highly multi-disciplinary 4-year doctoral programme, which works in partnership with a large base of industrial and external sponsors on a variety of projects. The four main research themes within the Centre are 1) Energy Materials; 2) Catalysis; 3) Healthcare Materials; and 4) 'Smart' Nano-Materials, which will be underpinned by an extensive training and research programme in (i) Software Development together with the Hartree Centre, Daresbury, and (ii) Materials Characterisation techniques, employing Central Facilities in partnership with ISIS and Diamond. Students at the M3S CDT follow a tailor-made taught programme of specialist technical courses, professionally accredited project management courses and generic skills training, which ensures that whatever their first degree, on completion all students will have obtained thorough technical schooling, training in innovation and entrepreneurship and managerial and transferable skills, as well as a challenging doctoral research degree. Spending >50% of their time on site with external sponsors, the students gain first-hand experience of the demanding research environment of a competitive industry or (inter)national lab. The global and national importance of an integrated computational and experimental approach to the Materials Sciences, as promoted by our Centre, has been highlighted in a number of policy documents, including the US Materials Genome Initiative and European Science Foundation's Materials Science and Engineering Expert Committee position paper on Computational Techniques, Methods and Materials Design. Materials Science research in the UK plays a key role within all of the 8 Future Technologies, identified by Science Minister David Willetts to help the UK acquire long-term sustainable economic growth. Materials research in UCL is particularly well developed, with a thriving Centre for Materials Research, a Materials Chemistry Centre and a new Centre for Materials Discovery (2013) with a remit to build close research links with the Catalysis Technology Hub at the Harwell Research Complex and the prestigious Francis Crick Institute for biomedical research (opening in 2015). The M3S will work closely with these centres and its academic and industrial supervisors are already heavily involved with and/or located at the Harwell Research Complex, whereas a number of recent joint appointments with the Francis Crick Institute will boost the M3S's already strong link with biomedicine. Moreover, UCL has perhaps the largest concentration of computational materials scientists in the UK, if not the world, who interact through the London-wide Thomas Young Centre for the Theory and Simulation of Materials. As such, UCL has a large team of well over 100 research-active academic staff available to supervise research projects, ensuring that all external partners can team up with an academic in a relevant research field to form a supervisory team to work with the Centre students. The success of the existing M3S CDT and the obvious potential to widen its research remit and industrial partnerships into topical new materials science areas, which lie at the heart of EPSRC's strategic funding priorities and address national skills gaps, has led to this proposal for the funding of 5 annual student cohorts in the new phase of the Centre.

Recent estimates suggest there are now over 3 billion mobile phones and 1 billion personal computers in use worldwide. The total energy consumption associated with such devices is growing and is predicted to triple by 2030, becoming equivalent to the current residential electricity consumption of the US and Japan combined (Gadgets and Gigawatts - Policies for Energy Efficient Electronics, 2009). Given the environmental costs associated with energy generation and storage, improving the energy efficiency of electronic devices is now an urgent priority. The key to reducing the energy consumption of electronic devices is better control of the electric currents flowing within them. Crucially, this is often dependent on the properties and robustness of thin metal-oxide (MO) films. For example, insulating MO films are used to separate metallic and semiconducting electrodes in transistors. During operation, the voltage applied between the electrodes causes current to leak through the MO film, causing wasteful energy consumption. Over time, leakage current can grow and lead to a more terminal problem whereby the MO film abruptly becomes highly conducting, a process known as breakdown. These deleterious effects are becoming increasingly important as transistors are ever further miniaturised to meet consumer demand for increasingly powerful devices. On the other hand, the reversible switching of a MO film between insulating and conducting states by applying voltages has recently received interest as the basis for a non-volatile and low-power memory technology. For transistors, memristors and many other oxide-based electronic devices there is speculation that electron trapping by defects, polycrystallinity, electric fields and redox reactions at the electrode, all play important roles, however, there are few theoretical models which take these factors into account. The main aims of this fellowship are to learn how structure and composition are related to the electrical properties of thin MO films sandwiched between conducting electrodes, and to understand the mechanisms responsible for the transformation of these properties by application of a voltage. This will provide a framework for understanding leakage current and resistive switching in MO films, and allow strategies to control these effects to be investigated. Materials modelling can play a crucial role in addressing these aims by elucidating processes taking place over a wide range of time- and length-scales, and identifying the critical material parameters. The usual modelling approach is first to determine the equilibrium structure, then to calculate the corresponding electronic properties and current. However, this does not allow for the possibility that the non-equilibrium flow of electrons can modify the structure of the material, e.g. by field driven ion diffusion and local heating. Considering such non-equilibrium effects is essential to be able to model breakdown and resistance switching, and is also important for other processes involving correlated electron-ion dynamics, such as radiation damage. Therefore, the development of a new integrated approach is proposed that can describe the feedback between electron and ion dynamics consistently, resulting in dynamically evolving non-equilibrium structure and properties. It will combine several levels of theoretical modelling to describe the polycrystalline film structure, including defects and interfaces, the associated electronic and thermodynamic properties, and the coupled non-equilibrium dynamics of both electrons and ions. Through close collaboration with project partners, models will be tested and refined. Ultimately, this will feed into the electronics industry, leading to the design of more efficient and more reliable devices. In the later stages of the project the methodologies developed will be extended to address related materials challenges for applications including solid oxide fuel cells and batteries.

The main goal of this project is to develop a fundamental understanding and applications of resistive switching in silicon-rich oxide. This may lead to a breakthrough in low-cost on-chip integration of Resistive Random Access Memory (RRAM) devices with Si microelectronics. To achieve that we will carry out detailed experimental studies of switching; develop a physical switching model; apply this model to design and fabricate demonstrator devices; characterise the devices, and develop circuit-level models for systems incorporating Si RRAM and hence extend the capabilities of Si microelectronics into new domains and applications. RRAM devices are components whose electrical resistance can be varied by applying an appropriate voltage. They are promising candidates for next generation electronic memories, offering a number of significant advantages over conventional Flash memory, including: very high packing density; fast switching; low energy switching; 3D integration to further increase memory capacity; ease of processing. Existing RRAM technologies are primarily based on metal oxide materials. However, Si- based devices have a number of advantages, including ease of integration with silicon CMOS processing technology, along with the possibility to tailor their electrical properties by varying programming voltage pulses. RRAM devices have potential applications beyond memory: if the device resistance can be continuously varied they may behave in a similar way to neurons, and may therefore be used in novel neural networks or other processing architectures. Also, as resistive switching shares many of the features of oxide failure in CMOS devices, the results from a study of RRAM will yield valuable information that may help reduce device failure, or even recovering damaged devices. We have recently developed a Si/SiO2 RRAM. Unlike competing technologies, it does not rely on the diffusion of metal ions, can be fabricated only from Si and SiO2, and operates in ambient conditions. Resistance contrast is up to 1,000,000, switching time <90ns, and switching energy 1pJ/bit or lower. Scanning Tunnelling Microscopy suggests individual switching elements as small as 10nm. Devices can be cycled thousands of times and can be operated in either unipolar or bipolar modes, with different characteristics in each: in the former, binary switching between discrete levels can be achieved, while in the latter we are able to continuously vary the device resistance, opening up the possibility of analogue devices such as memristors. Our devices are an alternative to existing metal oxide-based devices. The Si/SiO2 system is the building block of Si CMOS technology - our devices require no other material. We have found that the externally-set current compliance required for reliable resistive switching in metal oxide systems is not necessary in SiOx devices - asymmetric doping of the structure produces intrinsic self-limiting. In addition, the high degree of nonlinearity inherent in our semiconductor-based RRAM devices mitigates the problem of parasitic leakage currents in arrays of RRAM devices. Our project will go further than experimental studies of Si/SiO2 RRAM devices. We will also develop comprehensive theoretical models for the resistance switching process, and circuit-level models to investigate the application of our RRAM devices in real systems. Our approach is novel and unique in that it goes all the way from the atomistic modelling and electrical characterization of materials and fundamental electronic and ionic processes involved in resistive switching, through the simulation and fabrication of experimental devices to their optimisation and potential implementation in technology. This can only be achieved via synergy of expertise available at UCL and Glasgow.