• 文献标题:   Theory of Floquet band formation and local pseudospin textures in pump-probe photoemission of graphene
  • 文献类型:   Article
  • 作  者:   SENTEF MA, CLAASSEN M, KEMPER AF, MORITZ B, OKA T, FREERICKS JK, DEVEREAUX TP
  • 作者关键词:  
  • 出版物名称:   NATURE COMMUNICATIONS
  • ISSN:   2041-1723
  • 通讯作者地址:   Stanford Univ
  • 被引频次:   97
  • DOI:   10.1038/ncomms8047
  • 出版年:   2015

▎ 摘  要

Ultrafast materials science promises optical control of physical properties of solids. Continuous-wave circularly polarized laser driving was predicted to induce a light-matter coupled state with an energy gap and a quantum Hall effect, coined Floquet topological insulator. Whereas the envisioned Floquet topological insulator requires high-frequency pumping to obtain well-separated Floquet bands, a follow-up question regards the creation of Floquet-like states in graphene with realistic low-frequency laser pulses. Here we predict that short optical pulses attainable in experiments can lead to local spectral gaps and novel pseudospin textures in graphene. Pump-probe photoemission spectroscopy can track these states by measuring sizeable energy gaps and Floquet band formation on femtosecond time scales. Analysing band crossings and pseudospin textures near the Dirac points, we identify new states with optically induced nontrivial changes of sublattice mixing that leads to Berry curvature corrections of electrical transport and magnetization.