| Autor: |
Zandi, Omid, Sykes, Allan E, Cornelius, Ryan D, Alcorn, Frank M, Zerbe, Brandon, Duxbury, Phillip M, Reed, Bryan W, van der Veen, Renske M |
| Rok vydání: |
2020 |
| Předmět: |
|
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1038/s41467-020-16746-z |
| Popis: |
Understanding and controlling ultrafast non-equilibrium charge carrier dynamics is of fundamental importance in diverse fields of (quantum) science and technology. Here, we create a three-dimensional hot electron gas through two-photon photoemission from a copper surface in vacuum. We employ an ultrafast electron microscope to record movies of the subsequent electron dynamics on the picosecond-nanosecond time scale. After a prompt Coulomb explosion, the subsequent dynamics is characterized by a rapid oblate-to-prolate shape transformation of the electron gas, and exceptionally periodic and long-lived electron cyclotron oscillations inside the magnetic field of the objective lens. In this regime, the collective behavior of the oscillating electrons causes a transient, mean-field lensing effect and pronounced distortions in the images. We derive an analytical expression for the time-dependent focal length of the electron-gas lens, and perform numerical electron dynamics and probe image simulations to determine the role of Coulomb self-fields and image charges. This work paves the way for the direct visualization of cyclotron oscillations inside two-dimensional electron-gas materials and the elucidation of electron/plasma dynamics and properties that could benefit the development of high-brightness electron and X-ray sources. |
| Databáze: |
arXiv |
| Externí odkaz: |
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