Ke He, Tsinghua University
The quantum anomalous Hall (QAH) effect is a quantum Hall effect induced by spontaneous magnetization instead of an external magnetic field. The effect occurs in two-dimensional (2D) insulators with topologically nontrivial electronic band structure which is characterized by a non-zero Chern number. The experimental observation of the QAH effect in thin films of magnetically doped (Bi,Sb)2Te3 topological insulators (TIs) paves the way for practical applications of dissipationless quantum Hall edge states. Further studies in this direction require improved magnetic TI materials able to show the QAH effect at higher temperature and techniques to manipulate the chiral edge states. I will introduce the recent efforts to elevate the QAH temperature and to engineer QAH systems into various topological phases. I will also discuss the applications of the QAH states in creating and detecting Majorana modes and building a topological quantum computer.