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Negative Transit Time in Nontunneling Electron Transmission through Graphene Multilayers
E E Krasovskii1,2,3, R O Kuzian2,4
1Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, 20080 Donostia/San Sebastián, Basque Country, Spain.
Physical Review Letters
|April 11, 2025
Summary
Electron wave packet transit times through thin films reveal thickness-dependent behavior. Novel negative transit times were observed in graphene and other materials due to in-plane scattering.
Area of Science:
- Quantum mechanics
- Condensed matter physics
- Materials science
Background:
- Understanding electron dynamics in atomically thin materials is crucial for next-generation electronics.
- Electron transmission through crystalline films is governed by complex quantum mechanical interactions.
Purpose of the Study:
- To investigate the attosecond dynamics of electron transmission through atomically thin crystalline films.
- To analyze the temporal characteristics of electron wave packet propagation.
- To explore novel quantum phenomena like negative transit times and Wigner time delay.
Main Methods:
- Utilizing ab initio scattering theory to model electron propagation.
- Analyzing the relationship between band structure and wave packet transit time.
- Investigating scattering resonances and their impact on electron dynamics.
Main Results:
- Electron transit time saturates in forbidden gaps and oscillates in allowed bands with increasing film thickness.
- Discovery of hitherto unknown negative electron transit times in graphene, h-BN, and oxygen monolayers due to in-plane scattering.
- Wigner time delay diverges at scattering resonances, linked to the emergence of secondary diffracted beams.
Conclusions:
- The study provides insights into manipulating electron wave packet propagation timing without compromising transmitted intensity.
- Resonance-induced spatial reshaping of the wave packet offers potential for elucidating surface interactions.
- Findings advance the fundamental understanding of quantum electron transport in low-dimensional materials.
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