4 p.m. - 5 p.m. Location: SLC 1.102
Dr. Victor Galitski (Joint Quantum Institute, University of Maryland)
Topological states of quantum matter represent a rapidly developing area of research, where a fascinating variety of exotic phenomena occur ranging from unusual transport properties, where insulating and metallic behaviors co-exist, to fractionalized excitations that emerge at system’s defects. In this talk I will review recent theoretical and experimental work on a new class of topological material system – topological Kondo insulators, which appear as a result of interplay between strong correlations and spin-orbit interactions. I will start with introducing the by now standard theory of topological band insulators and explain the Fu-Kane method to calculate the topological index for time-reversal-invariant band structures in three dimensions. The method will be used to show that hybridization between the conduction electrons and localized magnetic moments in certain heavy fermion compounds gives rise to interaction-induced topological insulating behavior. I will also discuss recent experimental results, which have confirmed our predictions in the Samarium hexaboride heavy fermion compound, where the long-standing puzzle of the residual low-temperature conductivity has been shown to originate from topological surface states. This material system may represent the first true topological insulator observed experimentally with low-temperature transport dominated by the surface and essentially no conduction in the bulk. In conclusion, I will mention our ongoing experiment-theory collaborative work, which focuses on very unusual non-linear transport properties of Samarium hexaboride, which may be used to engineer new quantum devices.