FRUSTRATED MAGNETISM IN SPIN-ORBIT COUPLED MATERIALS

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TECHNICAL SUMMARYThis award supports theoretical research aimed at achieving a fundamental understanding of various frustrated quantum magnets, both of localized and itinerant kind. It consists of three research directions:(1) The first addresses the unusual features of the magnetization process of frustrated antiferromagnets, and in particular the appearance and the stability of magnetization plateau phases in the system of strongly correlated, but itinerant, electrons on a triangular lattice. The PI and his group will study the transition to the metallic state at fixed magnetization and explore the sensitivity of the quantum critical point separating the co-planar and cone phases with respect to exchange anisotropy and interlayer interactions between spins as well as the magnitude of the microscopic spin. (2) The second direction is devoted to exploiting spin-orbital interactions, which are always present in experimental materials of interest, in order to probe fractionalized spinon excitations of the spin-liquid ground states. (3) The third direction consists of the development and application of a novel numerical approach, called Diagrammatic Monte Carlo, to finite temperature properties of frustrated antiferromagnets. This method is free from the finite-size effect which severely restricts more traditional numerical approaches and is expected to open a new route for describing the cooperative paramagnetic states of experimentally relevant materials.This award also supports the PI's educational activities that are closely tied with the outlined research plan. These include the training and education of graduate and undergraduate students in analytical and numerical condensed matter physics. In addition, the PI will develop a novel graduate course, Physics of Modern Materials, that is aimed at exposing the students to newest developments in condensed matter physics. The PI will continue to maintain a research website which summarizes the main research developments in terms accessible to graduate students as well as to professional colleagues.NON-TECHNICAL SUMMARYThis award supports theoretical research aimed at achieving a fundamental understanding of "frustrated" magnetic materials. Frustration is a technical term used to describe situations when different microscopic elements, such as microscopic magnetic moments inside a magnetic material, are unable to find equilibrium configurations in which all members of the ensemble have minimal possible energy contributions. Thus, a finite fraction of microscopic moments can be viewed as being constantly "on the move" to look for a more satisfactory arrangement, which never materializes. This situation leads to the appearance of very unusual magnetic structures and peculiar quantum dynamics which persists over a wide range of temperatures, magnetic fields and other experimentally controlled external parameters. The PI will use analytical methods and develop new numerical techniques to explore a variety of fundamentally important frustrated magnet systems. This award also supports the PI's educational activities that are tied closely with the outlined research plan. These include the training and education of graduate and undergraduate students in analytical and numerical condensed matter physics. In addition, the PI will develop a novel graduate course, Physics of Modern Materials, that is aimed at exposing the students to newest developments in condensed matter physics. The PI will continue to maintain a research website which summarizes the main research developments in terms accessible to graduate students as well as to professional colleagues.