Electronic structure of solids and interfaces with strong electron-electron/Boson interactions

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Our research is focused on obtaining a detailed understanding of the relationship between the chemical composition, the atomic and the electronic structure of materials and their physical properties, including the electrical, magnetic, optical and thermal properties that are determined primarily by valence electrons of the atoms and their propagation in the solid. In transition metal and rare earth compounds, the partially filled valence shell electrons have strong interactions resulting in alignment of their spins and ordering the occupation of the orbitals. This leads to, for example, local magnetic moments and electrical quadrupole moments, which order in the solid to form interesting magnetic and orbital ordering patterns with new and exotic physical properties.The physics of atoms and ions in solids and the propagation of electrons between them, coupled with the motions of the atoms, lie at the heart of being able to predict which structures, compositions and micro structures could lead to new and interesting physical properties. We develop theoretical and experimental methods to study the electronic structure of these correlated electron systems in detail. With the new X-ray spectroscopy beam line recently developed at the Canadian Light Source, we study the electronic structure of solids on an atomic scale. This includes the electronic structure of deeply buried interfaces in heterostructures of transition metal oxides. These interfaces have fascinating new properties such as the superconducting interfaces formed between two judiciously selected parent electrical insulators.We propose new directions in interface engineering, utilizing our newly developed molecular beam epitaxy method for atom-by-atom growth of new materials and interfaces. We also propose the development of a new and world-leading electron energy loss spectroscopy facility with unmatched energy and momentum resolution. This will be complimented with non-resonant hard x-ray inelastic scattering with high energy and momentum resolution to determine the large momentum energy loss region. This is crucial to determine the Crystal Local Field Corrections, which determine the electron-electron and electron phonon interactions in these correlated electron systems modified by screening and electronic solvation effects.We also propose to develop the theoretical and computational methods needed to interpret the experimental result and to predict potentially new structures with interesting physical properties. We note that this information is of crucial importance in systems that have a very non-uniform electron density and polarizability, as is mostly the case in the materials of interest here. This will be done in the strongly collaborative atmosphere of the Stewart Blusson Quantum Matter Institute and in collaboration with the UBC-Max Planck-U Tokyo Centre for Quantum Materials.