• 文献标题:   Topological resonance and single-optical-cycle valley polarization in gapped graphene
  • 文献类型:   Article
  • 作  者:   MOTLAGH SAO, NEMATOLLAHI F, APALKOV V, STOCKMAN MI
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW B
  • ISSN:   2469-9950 EI 2469-9969
  • 通讯作者地址:   Georgia State Univ
  • 被引频次:   6
  • DOI:   10.1103/PhysRevB.100.115431
  • 出版年:   2019

▎ 摘  要

For gapped graphene, we predict that an intense ultrashort (single-oscillation) circularly polarized optical pulse can induce a large population of the conduction band and a large valley polarization. With an increase in the band gap, the magnitude of the valley polarization gradually increases from zero (for the native gapless graphene) to a value on the order of unity. The energy bandwidth of the electrons excited into the conduction band can be very large (greater than or similar to 10 eV for a reasonable pulse amplitude of similar to 0.5 V/angstrom). These phenomena are due to the effect of topological resonance: The matching of the topological (geometric) phase and the dynamic phase. Gapped graphene with a tunable band gap can be used as a convenient generic model of two-dimensional semiconductors with honeycomb generic lattice structures and broken inversion symmetry, such as transition-metal dichalcogenides.