Void-Defect Induced Magnetism and Structure Change of Carbon Materials -Ⅰ: Graphene Nano Ribbon

Void-defect is a possible origin of ferromagnetic-like feature pure carbon material. Applying density functional theory to void-defect induced graphene-nano-ribbon (GNR), detailed relationship between multiple-spin-state and structure change was studied. An equilateral triangle an initial void having six electrons distorted isosceles by re-bonding atoms. Among spin-states Sz=0/2, 2/2, 4/2 6/2, the most stable state Sz=2/2. The case Sz=4/2 remarkable that flat ribbon turned three dimensionally curled one highly polarized spin configuration at edges. Total energy very close Sz=2/2, which suggests coexistence ribbon. As model dimensional graphite, bi-layered AB stacked GNR analyzed for cases different position α-site β-site. Spin distribution limited surface layer, nothing back layer. Distorted show 60degree clockwise rotation from α- β-site, consistent with experimental observation using scanning tunneling microscope. This study revealed in induces unusual state, usual ferromagnetic one.