Recent progress and perspectives in topological insulators: quantum Hall effects, ballistic vs. diffusive regimes and Anderson transitions

Date :From 2016-04-11 To 2016-04-29
Advisory committee :
Local coordinators :
International coordinators :Victor Kagalovsky(Shamoon College of Engineering), Alexander L. Chudnovskiy(University Hamburg), Sergey Kravchenko(Northeastern University Boston), Xin-Cheng Xie(Peking University), Sen Zhou(Institute of Theoretical Physics, CAS)
The discovery of topological insulators (TI) opened a new and vividly developing field of theoretical and experimental investigations. In 2D TI, the existence of topologically protected extended edge states together with insulating bulk suggests a close relation between the physics of topological insulators and integer quantum Hall effect (IQHE) systems. This analogy naturally puts forward a question about the pendant of the metallic critical state that is observed at the transition between the quantum Hall plateaus but has neither been observed experimentally nor investigated theoretically in TI. Recently, it was shown theoretically that the extended state separates the ground states with different topological numbers in disordered 1D systems as the strength of disorder is changed. Generalization of that physical picture to 2D and 3D systems with the symmetry of TI would mark a major break-through in our understanding of the world of topologically nontrivial states of matter. In this program, we bring together theorists and experimentalists working in the field of TI, specifically addressing the role of disorder in 2D and 3D TI. The planning of experimental measurements of transition between the states of different topological order raises the problem of current distribution on the surface and in the volume of 3D TI. We expect that close collaboration between the leading theorists and experimentalists in the field during this program will result in new experimental studies and detailed theoretical calculations of current distribution in 2D and 3D TI, which will later be usedto locate a possible transition between different topological orders.