Non-Collinear Orbital-induced Planar Quantum Anomalous Hall Effect

Area of Science:

• Condensed Matter Physics
• Materials Science
• Topological Physics

Background:

• Quantum anomalous Hall effect (QAHE) is a quantum phenomenon with potential applications in low-power electronics.
• Designing novel materials with tunable topological properties remains a key challenge.

Purpose of the Study:

• To develop a theoretical model for planar quantum anomalous Hall effect (PQAHE) utilizing noncollinear orbitals.
• To identify experimentally realizable materials exhibiting PQAHE.
• To explore the tunability of topological phases in PQAHE systems.

Main Methods:

• Development of a six-band tight-binding model based on a 2D star lattice with noncollinear orbitals.
• Inclusion of intrinsic spin-orbital coupling to map the topological phase diagram.
• First-principles calculations to identify the model in a specific 2D metal-organic framework (MOF).

Main Results:

• Demonstrated realization of Dirac-, Kagome-, and Four-band characteristics by varying noncollinear orbital orientation.
• Mapped a tunable topological phase diagram, showing PQAHE with Chern numbers +1 or -1.
• Identified the PQAHE model in the experimentally synthesized 2D MOF, Pr₂(C₆O₄Cl₂)₃.

Conclusions:

• Noncollinear orbitals are significant for designing PQAHE.
• The studied 2D MOF provides a practical platform for realizing PQAHE.
• This work enriches topological physics and expands the library of candidate topological materials.