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Exciton transport in atomically flat heterostructures: The appearance of negative diffusivity
N S Maslova1, V N Mantsevich1, P I Arseyev2
1Lomonosov Moscow State University, 119991 Moscow, Russia.
Physical Review. E
|August 19, 2025
Summary
This study reveals negative diffusivity in quasiparticle transport across material interfaces, impacting exciton dynamics in 2D systems. Findings offer insights into semiconductor material behavior and interface phenomena.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Semiconductor Physics
Background:
- Quasiparticles in semiconductors exhibit diverse propagation behaviors.
- Understanding transport phenomena at material interfaces is crucial for device applications.
Purpose of the Study:
- To theoretically analyze phonon-assisted transport of excited quasiparticles (excitons) in 2D systems at a 1D interface.
- To investigate exciton dynamics under relaxation and external force fields.
Main Methods:
- Utilized a quasi-classical kinetic equation approach.
- Analyzed exciton transport in both homogeneous and inhomogeneous material systems.
- Studied mean-squared displacement for various system parameters.
Main Results:
- Observed negative diffusivity in exciton transport across the interface in both homogeneous and inhomogeneous cases.
- Identified distinct short- and long-time domain behaviors in mean-squared displacement.
- Demonstrated the influence of differing diffusion coefficients on transport dynamics.
Conclusions:
- Phonon-assisted exciton transport can exhibit negative diffusivity at interfaces between dissimilar 2D materials.
- The interface properties and material characteristics significantly affect quasiparticle dynamics.
- Results provide a theoretical framework for understanding transport in complex semiconductor heterostructures.
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