Local microwave sensing of excitons and their electrical environment

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Atomically thin transition metal dichalcogenides (TMDs) exhibit unique optical properties crucial for advanced electronics and fundamental physics.
• Studying excitonic responses at subwavelength scales presents significant challenges for conventional probing methods.

Purpose of the Study:

• To introduce and validate a novel cryogenic scanning probe technique for localized exciton analysis.
• To investigate exciton-environment interactions in monolayer MoSe2 at the nanoscale.

Main Methods:

• Development and application of exciton-resonant microwave impedance microscopy (ER-MIM) at cryogenic temperatures (1.5K).
• Measurement of excitonic responses in a monolayer MoSe2 device.
• Integration of deep learning for precise electrical parameter extraction.

Main Results:

• Identification of exciton polarons and their Rydberg states in monolayer MoSe2.
• Systematic revelation of local and nonlocal effects on excitons, including carrier density, electric fields, and dielectric screening.
• Quantified, exciton-assisted nanoscale electrometry achieved through deep learning analysis.

Conclusions:

• ER-MIM is established as a powerful optoelectronic sensing platform for probing exciton-environment interactions.
• The study provides new insights into exciton behavior in 2D materials.
• Opens avenues for exciton-based quantum control and novel device technologies.