Engineering Plateau Phase Transition via Tailoring Structure 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 magnetic domains and then re-converges back to a single magnetic domain. The layer structure has been established as an external knob for adjusting the Chern number C of the QAH insulators. In this work, we employed molecular beam epitaxy (MBE) to grow magnetic TI multilayers with an asymmetric layer structure and realize the magnetic field-driven plateau phase transition between two QAH states with odd Chern number change DC. In a single multilayer structure with C = ±1 and C = ±2 QAH states, we found two characteristic power-law behaviors between temperature and the scaling variables on the magnetic field at the transition points. We extracted two critical exponents κ₁ ~0.390 and κ₂ ~0.388 for the plateau phase transitions with DC = 1 and DC = 3 in QAH insulators, respectively. This work will motivate further investigations into the critical behaviors of plateau phase transitions with different DC in QAH insulators and provide new opportunities for the development of QAH chiral edge current-based electronic and spintronic devices.