• 文献标题:   Optical selection rules of zigzag graphene nanoribbons
  • 文献类型:   Article
  • 作  者:   SAROKA VA, SHUBA MV, PORTNOI ME
  • 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:   Univ Exeter
  • 被引频次:   16
  • DOI:   10.1103/PhysRevB.95.155438
  • 出版年:   2017

▎ 摘  要

We present an analytical tight-binding theory of the optical properties of graphene nanoribbons with zigzag edges. Applying the transfer matrix technique to the nearest-neighbor tight-binding Hamiltonian, we derive analytical expressions for electron wave functions and optical transition matrix elements for incident light polarized along the structure axis. It follows from the obtained results that optical selection rules result from the wave function parity factor (-1)(J), where J is the band number. These selection rules are that Delta J is odd for transitions between valence and conduction subbands and that Delta J is even for transitions between only valence (conduction) subbands. Although these selection rules are different from those in armchair carbon nanotubes, there is a hidden correlation between absorption spectra of the two structures that should allow one to use them interchangeably in some applications. The correlation originates from the fact that van Hove singularities in the tubes are centered between those in the ribbons if the ribbon width is about a half of the tubes circumference. The analysis of the matrix elements dependence on the electron wave vector for narrow ribbons shows a smooth nonsingular behavior at the Dirac points and the points where the bulk states meet the edge states.