Soft chemical control to achieve new layered architectures and strongly correlated states.

Solid state chemistry involves the synthesis of (normally) crystalline solids (compounds resembling minerals) and optimisation of their compositions so as to realise particular physical or chemical properties, such as conductivity or magnetism. Often these compounds are synthesised at high temperatures so that the ionic mobility is high enough for the reactions to proceed. Under this thermodynamic control of the synthesis the range of compositions available for a particular combination of elements may be limited. So complementary low temperature (e.g. at room temperature, or even below) syntheses are another way of changing the chemical composition and this may enable a wider range of chemical compositions to be attained. The low temperature chemistry, normally an intercalation or a deintercalation, is possible if the compound supports high mobility of some of its constituent ions. The work proposed here starts from the demonstration that deintercalation chemistry of a series of layered transition metal compounds is possible and does have profound effects on the electronic properties. The targets are compounds where compositional tuning may be carried out continuously and over a wide compositional range. The transition metals in these compounds and the two-dimensional crystal structures have been chosen so as to yield strongly-correlated-electron systems where the electronic behaviour is not easy to predict due to several competing factors, and where unusual electronic phenomena, such as superconductivity, magnetoresistance, high thermoelectric power and metal-to-insulator transitions are often found. In addition to producing new compositions, we will explore ways in which the chemistry can be applied to large crystals of the compounds in order to give better insight into their microscopic properties.

The following sections summarise who might benefit from this research project and how they might benefit.

(i) People. The PDRA working on the project will be an immediate beneficiary of the research. They will gain expertise in challenging chemical synthesis, structural measurements using international facilities and a range of physical property measurements. This diverse experience will make them very well suited to a career as an academic, and a researcher at a national facility or in a role in a technology company where their problem solving skills will be valuable. Prospective PhD and masters level students and visiting scholars will benefit from being attracted to this project.

(ii) Academic Beneficiaries. These have been identified in detail in a separate section of the form. They will benefit from the research during the period of the grant and beyond. The work will generate new knowledge and so beneficiaries of this will be a range of computational, theoretical and experimental scientists in universities and at international facilities who will benefit from the discovery of new compounds with new properties and the development of the synthesis techniques for exploring compositional space.

(iii) Society. The aim of performing this research is to identify compounds with a range of physical properties. Some of these compounds may then become incorporated as materials present in electronic devices. The work described here may also trigger other research projects that eventually lead to new device materials. The ultimate development of new technological materials from this research likely lies beyond the timeframe of the grant itself, but these may ultimately improve sustainability and the quality of life.

(iv) Economy. As with the societal benefits, economic benefits will likely be realised well beyond the course of the grant. If some of these compounds or ideas are incorporated into device materials, then the benefits to the economy will come from the global sales of such devices and any gains in efficiencies that are afforded by the devices. The level of technological exploitation of the research proposed here is impossible to predict because the properties of the compounds are unknown, and are rather difficult to predict with any certainty. Nevertheless, new materials developments consistently drive advances in technology, as demonstrated by the now-widespread use of Li-ion batteries, magnetic sensors, photovoltaics and liquid crystals, all the product of fundamental research in chemistry and physics.