Parity-Anomaly Quantum Anomalous Hall State in Mechanically Assembled Topological Insulator/Magnet Heterostructures

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Phenomena

Background:

• Quantized anomalous Hall effects (QAHE) offer unique electronic properties like dissipationless edge states.
• Current QAHE realizations are limited to very low temperatures, hindering practical applications.
• Magnetically-doped topological insulators (TIs) achieve QAHE up to several Kelvin, while proximity-coupled heterostructures show limited success.

Purpose of the Study:

• To demonstrate a higher-temperature realization of a QAHE state using proximity-coupled TI/magnet heterostructures.
• To investigate the parity anomaly state (Hall conductivity e²/2h) in engineered van der Waals heterostructures.
• To overcome the temperature limitations of previous proximity-coupled systems.

Main Methods:

• Fabrication of TI/magnet bilayers via mechanical assembly of van der Waals layers.
• Characterization of electronic transport properties, specifically Hall conductivity.
• Experimental verification of the parity anomaly state at zero magnetic field (B=0).

Main Results:

• Demonstration of the parity anomaly state with Hall conductivity e²/2h at temperatures up to 10 K.
• Achieved a 100-fold enhancement in operating temperature compared to previous deposition-grown proximity-coupled heterostructures.
• Successful realization of QAHE in mechanically assembled van der Waals heterostructures.

Conclusions:

• Mechanically assembled van der Waals TI/magnet bilayers enable higher-temperature QAHE.
• This approach significantly advances the potential for practical applications of dissipationless electronic transport.
• The parity anomaly state is a viable platform for exploring QAHE at accessible temperatures.