Orientation-selective spin-polarized edge states in monolayer NiI₂

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Computing

Background:

• Two-dimensional (2D) materials with spin-polarized edge states are key for spintronics and quantum computing.
• Tailoring 2D semiconductors with bulk-boundary correspondence offers a route to stable edge states.
• Layered NiI₂ is a 2D type-II multiferroic semiconductor with spiral spin ordering and electric polarization.

Purpose of the Study:

• Investigate the 1D spin-polarized edge states in monolayer NiI₂, particularly at the monolayer limit.
• Explore the synthesis and characterization of monolayer NiI₂.
• Determine the preferential alignment of these edge states.

Main Methods:

• Successful synthesis of monolayer NiI₂ on Au(111) using molecular beam epitaxy.
• Spin-polarized scanning tunneling microscopy/spectroscopy (SP-STM/S) to visualize edge states.
• First-principles calculations to confirm theoretical predictions.

Main Results:

• SP-STM/S experiments visualized orientation-selective spin-polarized edge states in monolayer NiI₂ islands.
• First-principles calculations confirmed that these edge states align selectively along Ni-terminated edges.
• The study successfully synthesized monolayer NiI₂, a crucial step for further research.

Conclusions:

• Monolayer NiI₂ possesses orientation-selective spin-polarized edge states.
• These edge states are preferentially located at Ni-terminated edges, offering control over their orientation.
• The findings pave the way for developing novel spintronic devices utilizing 2D magnetic semiconductors.