Ongoing Projects

The work in the Bobev research group addresses important issues related to the understanding of the relationships among the composition, structure, and electronic structure in complex intermetallic compounds and their properties. Our efforts are currently focused in two research directions, both of which cut across the traditional boundaries of the science disciplines – synthetic inorganic chemistry, theoretical chemistry, condensed-matter physics, X-ray crystallography, materials science, etc.
The first thrust area fall under the title “Structural relationships and magnetism in compounds of the lanthanide elements”. This research project is aimed at studying the fundamental chemistry and physics of new intermetallic compounds that can be dubbed for short “magnetic materials”. They have implications that stretch far beyond magnetism and into superconductivity, and although much research has already been done in this field, still surprisingly little is known about the basic principles, which make magnetic and superconductive materials behave as such. With this motivation in mind, our general long-term goal here is the discovery of classes of new lanthanide-based compounds with unusual magnetic and electronic properties. We seek to develop a rationale for finding new magnetic materials and for the effective optimization of existing ones that is not based empirical tenets, but instead, relies on understanding the principles governing the structures and properties.
The second research theme in the Bobev group is broadly related to materials for solid-state energy conversion. This large interdisciplinary project is driven by two of the greatest challenges of our time – energy beyond fossil fuels and environment. We embarked on this endeavor, Novel compounds for thermoelectric applications, recognizing that the technologies based on thermoelectricity are environmentally benign and have the potential for widespread applications; however, they are not yet part of the everyday life because of their low efficiency. This limitation, in essence, is a result of the unsatisfactory properties of almost all currently available materials. From the standpoint of synthetic chemists, we see both a societal need and a scientific opportunity to contribute to this area by synthesizing fundamentally new materials with higher thermoelectric efficiency. We believe a breakthrough can be achieved by bringing together (in one material) the desirable heat and charge transport properties of semiconductors and the magnetism and the correlated electron behavior, which are signatures of the d- or f-elements. Along similar lines, we also take an interest in open framework structures, clathrates in particular, where the host framework provides a good power factor (a combination of the thermopower, α, and the electrical conductivity, σ), while the guest atoms’ vibrations are responsible for acoustic phonons that lead to lowering the thermal conductivity (κ) and maximizing the thermoelectric figure of merit ZT = α2σT/κ. Our efforts here again are focused on the synthesis and the structural characterization of new solids – an experimental endeavor that heavily relies upon rationally designed syntheses, coupled with thorough and systematic structural studies and property measurements.