• 文献标题:   Single-layer and bilayer graphene superlattices: collimation, additional Dirac points and Dirac lines
  • 文献类型:   Review
  • 作  者:   BARBIER M, VASILOPOULOS P, PEETERS FM
  • 作者关键词:   graphene, electron transport, twodimensional crystal
  • 出版物名称:   PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY AMATHEMATICAL PHYSICAL ENGINEERING SCIENCES
  • ISSN:   1364-503X
  • 通讯作者地址:   Univ Antwerp
  • 被引频次:   52
  • DOI:   10.1098/rsta.2010.0218
  • 出版年:   2010

▎ 摘  要

We review the energy spectrum and transport properties of several types of one-dimensional superlattices (SLs) on single-layer and bilayer graphene. In single-layer graphene, for certain SL parameters an electron beam incident on an SL is highly collimated. On the other hand, there are extra Dirac points generated for other SL parameters. Using rectangular barriers allows us to find analytical expressions for the location of new Dirac points in the spectrum and for the renormalization of the electron velocities. The influence of these extra Dirac points on the conductivity is investigated. In the limit of delta-function barriers, the transmission T through and conductance G of a finite number of barriers as well as the energy spectra of SLs are periodic functions of the dimensionless strength P of the barriers, P delta(x)=V(x)/hv(F), with v(F) the Fermi velocity. For a Kronig-Penney SL with alternating sign of the height of the barriers, the Dirac point becomes a Dirac line for P = pi/2 + n pi with n an integer. In bilayer graphene, with an appropriate bias applied to the barriers and wells, we show that several new types of SLs are produced and two of them are similar to type I and type II semiconductor SLs. Similar to single-layer graphene SLs, extra 'Dirac' points are found in bilayer graphene SLs. Non-ballistic transport is also considered.