Interlayer exciton flux amplification driven by strong exciton confinement

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Interlayer excitons (IXs) in van der Waals heterostructures are crucial for excitonic circuits.
• Understanding nanoscale IX transport mechanisms is essential for device advancement.
• Current knowledge of IX transport at the nanoscale is limited.

Purpose of the Study:

• To demonstrate an anomalous interlayer exciton transport regime in van der Waals heterostructures.
• To investigate the impact of nanoscale bandgap modifications on IX behavior.
• To establish a method for manipulating and probing IX transport at the nanoscale.

Main Methods:

• Utilized a controllable electro-plasmonic nanocavity for precise manipulation and probing of IXs.
• Engineered nanoscale bandgap gradients to confine IXs.
• Quantified IX diffusion current and drift under controlled conditions.

Main Results:

• Observed an anomalous IX transport regime driven by nanoscale bandgap modifications.
• Demonstrated a nanoscale bandgap gradient that confines IXs, amplifying diffusion current by ~8,300% compared to microscale gating.
• Showed that this regime depends on the IX density gradient, not the total IX population.

Conclusions:

• Revealed a novel IX transport regime in van der Waals heterostructures.
• Established nanocavity confinement as a method to control exciton flux, decoupling efficiency from density constraints.
• Opened new avenues for designing reconfigurable excitonic devices.