Abstract
Topological insulators are materials that behave like ordinary insulators in their interiors, but have gapless modes on their boundaries. Recently, there has been increasing interest in many-body interaction in topological states of matter. The electron-electron interaction accompanied with disorders in topological insulators may induce novel phenomena, such as weak localization, and weak anti-localization of surface electrons. More recently, it has also been proposed that the interplay of interaction and impurity scatterings would generate a gap on the topological surface states with preserving time reversal symmetry.
This talk will focus on the study of electron-electron interaction on topological surface states with impurities. The background of topological surface states and several relevant works will be briefly reviewed. The proposed method, namely diagrammatic technique, will be introduced. The calculation of the topological invariant of quantum spin Hall systems subjected to perpendicular magnetic fields may also be presented.