Interlayer coupling induced quantum phase transition in quantum anomalous Hall multilayers

The ability to control topological quantum phases is central to advancing next-generation electronic technologies. The authors demonstrate here a quantum phase transition between quantum anomalous Hall states, with Chern numbers $C$=1 and 2, in magnetically doped topological insulator (TI) pentalayers. By systematically varying the thickness of the middle magnetically doped TI spacer layer, the authors identify interlayer coupling as the key driver of the transition. The finding opens new opportunities for chiral edge transport in device applications.