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Updated: Jan 9, 2026
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Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
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Orbital topology induced orbital Hall effect in two-dimensional insulators
Yueh-Ting Yao1, Chia-Hung Chu1, Arun Bansil2,3
1Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
Reports on Progress in Physics. Physical Society (Great Britain)
|December 9, 2025
Summary
Researchers discovered a new topological phase, orbital Chern insulators (OCIs), that explains the orbital Hall effect (OHE) in insulating materials. Monolayer blue phosphorene is identified as the first pure OCI, paving the way for new orbitronics technologies.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Topological phases in quantum materials exhibit unique Hall responses.
- The orbital Hall effect (OHE) in insulators is gaining attention, but its origins are unclear.
Purpose of the Study:
- Introduce orbital Chern insulators (OCIs) as a novel topological phase.
- Explain the origin of the OHE in insulating systems.
- Identify materials exhibiting OCI properties.
Main Methods:
- Developed a theoretical framework based on orbital topology for OCI characterization.
- Investigated monolayer blue phosphorene as a potential OCI candidate.
Main Results:
- Identified monolayer blue phosphorene as the first pure OCI with robust topological boundary states.
- Demonstrated that the OCI state in blue phosphorene is purely orbital-driven.
- Showed the OHE in OCIs is disentangled from spin and valley degrees of freedom.
Conclusions:
- OCIs offer a new explanation for the OHE in insulators.
- Blue phosphorene is a promising material for exploring orbital topology.
- This research opens new avenues for orbitronics-based technologies.
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