• 文献标题:   Unconventional double-bended saturation of carrier occupation in optically excited graphene due to many-particle interactions
  • 文献类型:   Article
  • 作  者:   WINZER T, MITTENDORFF M, WINNERL S, MITTENZWEY H, JAGO R, HELM M, MALIC E, KNORR A
  • 作者关键词:  
  • 出版物名称:   NATURE COMMUNICATIONS
  • ISSN:   2041-1723
  • 通讯作者地址:   Chalmers Univ Technol
  • 被引频次:   1
  • DOI:   10.1038/ncomms15042
  • 出版年:   2017

▎ 摘  要

Saturation of carrier occupation in optically excited materials is a well-established phenomenon. However, so far, the observed saturation effects have always occurred in the strong-excitation regime and have been explained by Pauli blocking of the optically filled quantum states. On the basis of microscopic theory combined with ultrafast pump-probe experiments, we reveal a new low-intensity saturation regime in graphene that is purely based on many-particle scattering and not Pauli blocking. This results in an unconventional double-bended saturation behaviour: both bendings separately follow the standard saturation model exhibiting two saturation fluences; however, the corresponding fluences differ by three orders of magnitude and have different physical origin. Our results demonstrate that this new and unexpected behaviour can be ascribed to an interplay between time-dependent many-particle scattering and phase-space filling effects.