Designing light-element materials with large effective spin-orbit coupling

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Chemistry

Background:

• Spin-orbit coupling (SOC) is crucial for phenomena like nontrivial band gaps but typically requires heavy elements, hindering material synthesis and applications.
• Enhancing SOC in light elements is essential for developing advanced functional materials and devices.

Purpose of the Study:

• To demonstrate a method for amplifying SOC effects in light elements (3d and 4d systems).
• To establish design principles and databases for identifying materials with enhanced SOC.
• To predict novel quantum anomalous Hall insulators.

Main Methods:

• Investigating the interplay between crystal symmetry and electron correlation in partially occupied orbital multiplets.
• Utilizing self-consistently reinforced orbital polarization as a key mechanism.
• Developing comprehensive databases of Wyckoff positions and site symmetries in 2D and 3D crystals.
• Screening a 2D material pool for potential high-temperature quantum anomalous Hall insulators.

Main Results:

• Identified that crystal symmetry and electron correlation can significantly enhance SOC in light elements.
• Provided design principles and databases for predicting enhanced SOC materials.
• Predicted nine 2D material candidates exhibiting high-temperature quantum anomalous Hall effects with large nontrivial band gaps (hundreds of meV).

Conclusions:

• The study offers an efficient strategy for discovering SOC-active materials, reducing the reliance on heavy elements.
• This approach facilitates the development of next-generation spin-orbitronic materials and devices.
• The findings pave the way for novel topological quantum phenomena in lighter material systems.