Special seminar

Speaker: Shinsei Ryu (UC Berkeley)
Title: Ten-fold classification of topological insulators and superconductors
Date (JST): Fri, Feb 05, 2010, 13:15 - 14:45
Place: Balcony A
Related File: 224.pdf
Abstract: Recently, a new type of insulators ("Z2 topological insulator") has been discovered.
They can be thought of as a close cousin of the integer quantum Hall effect (IQHE), but
different from the IQHE in many essential ways: Z2 topological insulators can exist only when time-reversal symmetry is respected, and can be either two- or three-dimensional. Furthermore, Z2 topological insulators are characterized by a binary
topological number, unlike the integral Hall conductivity in the IQHE. Recent experiments
confirmed HgTe quantum well and Bismuth-related materials indeed realize such non-trivial Z2 topological phases.
In this talk, we propose to integrate all known topological insulators, including the IQHE, Z2 topological insulators, and some topological superconductors, into a single "periodic table". It is an exhaustive classification scheme of electronic systems as well as superconductors in terms of discrete symmetries (such as time-reversal), and has an interesting periodic structure both in terms of types of discrete symmetries and spatial dimensions. Moreover, the proposed classification predicts a number of new topological insulators and superconductors. Possible detection of such topological phases in terms of their abnormal surface/edge transport will be also discussed.