Valley-Dependent Interlayer Excitons in Magnetic WSe₂/CrI₃

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Optics

Background:

• Heterostructures of 2D transition-metal dichalcogenides (TMDs) and ferromagnetic substrates are key for novel spin- and valleytronic devices.
• Understanding the interfacial coupling in these heterostructures is vital for device performance.

Purpose of the Study:

• To investigate the coupling between WSe2 K-valleys and a ferromagnetic CrI3 sublayer.
• To characterize the distinct properties of excitons in this WSe2/CrI3 heterostructure.
• To explore the role of magnetic and optical properties in optoelectronic device development.

Main Methods:

• Ab initio GW/Bethe-Salpeter equation calculations.
• Analysis of energy splitting and interlayer exciton character.
• Determination of g factors for exciton response to magnetic fields.

Main Results:

• Substantially different coupling of WSe2 K-valleys to the CrI3 sublayer observed.
• Excitons exhibit significantly different interlayer character, with charge transfer allowed at K̅⁻ but forbidden at K̅⁺.
• Distinct g factors of approximately -4.4 and -4.0 were calculated for the respective excitons.

Conclusions:

• The study establishes g factors as a tool to probe exciton character in TMD heterostructures.
• Detailed quantum-mechanical interplay between magnetic and optical properties is elucidated.
• Findings are essential for the targeted development of advanced optoelectronic devices.