Valleytronics: Fundamental Challenges and Materials Beyond Transition Metal Chalcogenides

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Valleytronics leverages the valley degree of freedom for energy-efficient information processing.
• Monolayer transition-metal dichalcogenides (TMDs) show promise due to spin-valley locking.
• Current limitations include short valley lifetimes, low operating temperatures, and inefficient light-valley conversion.

Purpose of the Study:

• To systematically review valley depolarization mechanisms and novel materials for valleytronics beyond TMDs.
• To discuss factors influencing valley lifetime, including intrinsic and extrinsic effects.
• To highlight emerging materials and strategies for improved valleytronic properties.

Main Methods:

• Review of existing literature on valley physics and valleytronics.
• Analysis of valley depolarization mechanisms (electron-electron, electron-lattice, defects).
• Introduction of novel materials and theoretical proposals for enhanced valley properties.

Main Results:

• Identified key factors limiting valley lifetime in current materials.
• Presented a range of novel materials and theoretical concepts for improved valleytronics.
• Discussed strategies involving spin-orbit coupling, electronic interactions, symmetry, structure, and defects.

Conclusions:

• Overcoming limitations in valley lifetime and operating temperature is crucial for practical valleytronics.
• Novel materials and approaches beyond TMDs offer potential for significant advancements.
• Further research is needed to realize functional valleytronic devices.