Engineering Plateau Phase Transition in Quantum Anomalous Hall Multilayers

The plateau phase transition in quantum anomalous Hall (QAH) insulators corresponds to a quantum state wherein a single magnetic domain gives way to multiple domains and then reconverges back to a single magnetic domain. The layer structure of the sample provides an external knob for adjusting the Chern number Cof the QAH insulators. Here, we employ molecular beam epitaxy to grow magnetic topological insulator multilayers and realize the magnetic field-driven plateau phase transition between two QAH states with odd Chern number change ΔC. We find that critical exponents extracted for the plateau phase transitions with ΔC= 1 and ΔC= 3 in QAH insulators are nearly identical. We construct a four-layer Chalker–Coddington network model to understand the consistent critical exponents for the plateau phase transitions with ΔC= 1 and ΔC= 3. This work will motivate further investigations into the critical behaviors of plateau phase transitions with different ΔCin QAH insulators.