Altermagnetism Induced Surface Chern Insulator

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Phenomena

Background:

• The quantized anomalous Hall effect (QAHE) is a key quantum phenomenon with potential spintronic applications.
• Topological crystalline insulators (TCIs) possess unique surface states with potential for novel electronic properties.
• Achieving QAHE typically requires significant magnetization, posing challenges for practical applications.

Purpose of the Study:

• To propose and demonstrate a novel pathway to realize the quantized anomalous Hall effect (QAHE).
• To achieve QAHE in a robust and switchable platform with near-vanishing magnetization.
• To explore the potential of altermagnetic materials coupled with TCIs for spintronics.

Main Methods:

• First-principles calculations were employed to study the electronic properties of heterostructures.
• A slab of topological crystalline insulator (TCI) SnTe was coupled to an altermagnetic RuO2 layer.
• The effect of altermagnetism on the topological surface states of the TCI was analyzed.

Main Results:

• Coupling an altermagnet (RuO2) to a TCI (SnTe) successfully gapped the topological surface states.
• A 7 meV gap was induced in the Dirac surface states of SnTe by the d-wave altermagnetism of RuO2.
• A finite anomalous Hall effect was observed, indicating the realization of QAHE.

Conclusions:

• The proposed altermagnet-TCI heterostructure provides a viable platform for realizing QAHE with significantly reduced magnetization.
• This approach is generalizable to other altermagnetic materials and TCIs, creating a family of topological heterostructures.
• The developed platform offers high tunability and promising applications in spintronics.