Designer Quantum States in Magnetic Topological Insulator Multilayers

Magnetic topological insulators (TIs) provide a highly tunable platform for engineering quantum states arising from the interplay between topology and magnetism. In this talk, based on projects conducted over the past five years, I will discuss how magnetically doped and undoped TI layers can be assembled as “topological Legos”. By controlling the layer thickness, magnetic doping, heterostructure architecture, and stacking sequence, we can realize designer quantum states and tunable topological transport. I will first introduce the realization of the axion insulator state in hundred-nanometer-thick magnetic TI sandwiches, demonstrating that axion physics can persist in the 3D limit [1]. Second, using an asymmetric magnetic TI sandwich structure, we observe the C = 1/2 parity anomaly state with the half-quantized chiral edge current under an in-plane magnetic field [2] and further demonstrate the interplay between boundary and bulk contributions in nonlinear topological transport [3]. Third, using magnetic TI pentalayer structures, we realize the magnetic field-driven plateau phase transitions between two quantum anomalous Hall states with designed changes in the Chern number [4]. Finally, I will briefly introduce the superlattice engineering of the magnetic Weyl semimetal phase in magnetic TI multilayers [5]. 

[1] Zhuo et al., Nat. Commun. 14, 7596 (2023)

[2] Zhuo et al., Phys. Rev. Lett. 136, 016601 (2026).

[3] Zhuo et al., Nat. Commun. (2026, in press).

[4] Zhuo et al., Nano Lett. 24, 6974-6980 (2024).

[5] Zhuo et al., Nature (2026, under review).