• 文献标题:   First-principles approach to monitoring the band gap and magnetic state of a graphene nanoribbon via its vacancies
  • 文献类型:   Article
  • 作  者:   TOPSAKAL M, AKTURK E, SEVINCLI H, CIRACI S
  • 作者关键词:   ab initio calculation, antiferromagnetic material, carbon, defect state, energy gap, ferrimagnetic material, magnetic semiconductor, magnetisation, metallisation, nanostructured material, spin polarised transport, transmission electron microscopy, vacancies crystal
  • 出版物名称:   PHYSICAL REVIEW B
  • ISSN:   1098-0121
  • 通讯作者地址:   Bilkent Univ
  • 被引频次:   102
  • DOI:   10.1103/PhysRevB.78.235435
  • 出版年:   2008

▎ 摘  要

Using first-principles plane-wave calculations we predict that electronic and magnetic properties of graphene nanoribbons can be modified by the defect-induced itinerant states. Structure optimization gives rise to significant reconstruction of atomic structure, which is in good agreement with transmission electron microscope images. The band gaps of armchair nanoribbons can be modified by hydrogen-saturated holes. The band-gap changes depend on the width of the ribbon as well as on the position of the hole relative to the edges of the ribbon. Defects due to periodically repeating vacancy or divacancies induce metallization as well as magnetization in nonmagnetic semiconducting nanoribbons due to the spin polarization of local defect states. Antiferromagnetic ground state of semiconducting zigzag ribbons can change to ferrimagnetic state upon creation of vacancy defects, which reconstruct and interact with edge states. Even more remarkable is that all these effects of vacancy defects are found to depend on their geometry and position relative to the edges. It is shown that these effects can, in fact, be realized without really creating defects.