Executive Summary : | A rich and varied selection of proposed experiments has been discussed here, and by combining the information gathered by our x-ray spectroscopic techniques, we will have the opportunity to develop a comprehensive understanding of electronic structure and conductivity transitions in Vanadates. We will use soft x-ray emission spectroscopy, soft x-ray absorption spectroscopy, resonant inelastic soft x-ray scattering, photoemission spectroscopy, and resonant inverse photoemission spectroscopy. We propose to measure band structures and Fermi surfaces in conducting Vanadates, to study the coupling between collective excitations and quasi-particles, and how this changes during conductivity transitions, to measure the local, site and element specific electronic structure, as well as the cation charge state, to measure orbital hybridization, and to measure element specific low energy valence excitations such as dd* and charge transfer excitations. The unifying theme of this project is to make accurate spectroscopic measurement of electronic structure in Vanadates in both conducting and insulating phases, thus allowing greater understanding of the rich physics of these materials, and in particular how to control their conductivity transitions. With its direct relevance for low-power information processing the ideas developed in this proposal will also be a key ingredient for developing a broader proposal for a new center focused on energy efficient computation. Lastly, our demonstration of controlled manipulation of transition metal doped Vanadates in magnetic thin films should generate excellent opportunities for technology transfer. |