Reducing carbon emissions and securing energy supplies are crucial international goals to which energy demand reduction must make a major contribution. On a national level, demand reduction, deployment of new and renewable energy technologies, and decarbonisation of the energy supply are essential if the UK is to meet its legally binding carbon reduction targets. As a result, this area is an important theme within the EPSRC's strategic plan, but one that suffers from historical underinvestment and a serious shortage of appropriately skilled researchers. Major energy demand reductions are required within the working lifetime of Doctoral Training Centre (DTC) graduates, i.e. by 2050. Students will thus have to be capable of identifying and undertaking research that will have an impact within their 35 year post-doctoral career. The challenges will be exacerbated as our population ages, as climate change advances and as fuel prices rise: successful demand reduction requires both detailed technical knowledge and multi-disciplinary skills. The DTC will therefore span the interfaces between traditional disciplines to develop a training programme that teaches the context and process-bound problems of technology deployment, along with the communication and leadership skills needed to initiate real change within the tight time scale required. It will be jointly operated by University College London (UCL) and Loughborough University (LU); two world-class centres of energy research. Through the cross-faculty Energy Institute at UCL and Sustainability Research School at LU, over 80 academics have been identified who are able and willing to supervise DTC students. These experts span the full range of necessary disciplines from science and engineering to ergonomics and design, psychology and sociology through to economics and politics. The reputation of the universities will enable them to attract the very best students to this research area.The DTC will begin with a 1 year joint MRes programme followed by a 3 year PhD programme including a placement abroad and the opportunity for each DTC student to employ an undergraduate intern to assist them. Students will be trained in communication methods and alternative forms of public engagement. They will thus understand the energy challenges faced by the UK, appreciate the international energy landscape, develop people-management and communication skills, and so acquire the competence to make a tangible impact. An annual colloquium will be the focal point of the DTC year acting as a show-case and major mechanism for connection to the wider stakeholder community.The DTC will be led by internationally eminent academics (Prof Robert Lowe, Director, and Prof Kevin J Lomas, Deputy Director), together they have over 50 years of experience in this sector. They will be supported by a management structure headed by an Advisory Board chaired by Pascal Terrien, Director of the European Centre and Laboratories for Energy Efficiency Research and responsible for the Demand Reduction programme of the UK Energy Technology Institute. This will help secure the international, industrial and UK research linkages of the DTC.Students will receive a stipend that is competitive with other DTCs in the energy arena and, for work in certain areas, further enhancement from industrial sponsors. They will have a personal annual research allowance, an excellent research environment and access to resources. Both Universities are committed to energy research at the highest level, and each has invested over 3.2M in academic appointments, infrastructure development and other support, specifically to the energy demand reduction area. Each university will match the EPSRC funded studentships one-for-one, with funding from other sources. This DTC will therefore train at least 100 students over its 8 year life.

This proposal is a collaboration between Professor A.M. Glazer (Crystallography Group, Clarendon Laboratory, Oxford) and Professors P.A. Thomas and M.E.Smith (Physics Dept., University of Warwick). The overall aim is to make for the first time, the crucial link between the absolute crystal structure of solid solutions in the lithium niobate and lithium tantalate series (hereafter LNT) and some of their highly unusual physical properties. A particular focus and point of key interest in this proposal is the existence of a composition in the series where the birefringence is zero at room temperature, so that the crystals become optically isotropic and yet remain electrically polar, which is an unique and extremely odd combination of properties in a nonlinear-optical, functional ferroelectric material. As part of our research programme, we intend to investigate this fascinating composition closely with a view to establishing whether such a material has potential as an unusually sensitive component in optically-based sensing applications, which are of high technical importance and timely relevance. For other LNT compositions, the point of optical isotropy can be obtained by raising the temperature, so that a locus line of zero birefringence points exists in the two-dimensional composition-temperature map. It is our goal to understand the occurrence of this behaviour across the LNT series from a fundamental point of view, whilst keeping in mind the potential for devices based on a combination of compositional and temperature tuning. In an entirely new and innovative twist, we will investigate for the first time the effect of the additional parameter pressure on the structure and properties of LNT in general, and particularly in the vicinity of the points of zero birefringence . Using birefringent imaging microsocopy, x-ray diffraction and solid state NMR at elevated pressures in a powerful combination of methodologies, we will map out the occurrence of the contours of zero birefringence in a three-dimensional parameter space to construct a composition-temperature-pressure (x-T-P) diagram. Since LN itself has large photoelastic and piezoelectric coefficients, we expect the pressure-dependence of the zero-birefringence points to be extremely high, thereby opening up the potential for a highly-sensitive and tunable pressure sensor. Our research will concentrate on expert x-ray structural analysis including absolute polarity determination (that is determination of the relationship between the direction of off-centre ions in the structures and the sense of electrical polarization) using anomalous x-ray scattering. These studies will be extended to non-ambient temperatures and pressures in order to fill out the parameter map and give the necessary data for interpretation of the zero birefringence contours. Alongside this, birefringent imaging microscopy will be used to map out the optical properties and thus, the zero birefringence contours of LNT compositions as a function of temperature, pressure and optical wavelength. Multinuclear solid state NMR will include 7Li, 17O and 93Nb, particularly to understand the role that octahedral distortions and cation displacements play in structure-property relations for compositionally-disordered crystals such as the LNT family. These will be extended to high temperatures using a dedicated probe constructed for 93Nb NMR and ultimately, to pressures of up to 5 GPa for sensitive zero-birefringence compositions as high-pressure NMR comes on-line. In summary, this research programme combines state-of-the-art methodologies to undertake novel science of a fundamental nature on the LNT series. It will both reveal new materials physics and answer some long-standing questions in the x-T-P space for LNT. Ultimately, and most speculatively, it may provide a new impetus for the development of devices based on this most unusual combination of physical properties in future years.