title: The origin of half-metallicity in conjugated electron systems--a study on transition-metal-doped graphyne.
abstract: We studied the mechanism of half-metallicity (HM) formation in transition-metal-doped conjugated carbon based structures by first-principles electronic structure simulations. It is found that the HM is a rather complex phenomenon, determined by the ligand field splitting of d-orbitals of the transition metal atoms, the exchange splitting and the number of valence electrons. Since most of the conjugated carbon based structures possess ligands with intermediate strength, the ordering of the d-orbital splitting is similar in all structures, and the HM properties evolve according to the number of valence electrons. Based on this insight we predict that Cr-, Fe- and Co-doped graphyne will show HM, while Mn- and Ni-doped graphyne will not. By tuning the number of valence electrons, we are thus able to control the emergence of HM and control the energy gaps evolving in the majority or minority spin channels.
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Lida
authors.initials: L
authors.lastname: Pan
authors.forename: Boqun
authors.initials: B
authors.lastname: Song
authors.forename: Jiatao
authors.initials: J
authors.lastname: Sun
authors.forename: Lizhi
authors.initials: L
authors.lastname: Zhang
authors.forename: Werner
authors.initials: W
authors.lastname: Hofer
authors.forename: Shixuan
authors.initials: S
authors.lastname: Du
authors.forename: Hong-jun
authors.initials: HJ
authors.lastname: Gao
mesh_terms: D004583:Electrons; D006108:Graphite / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D011789:Quantum Theory; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D008670:Metals; D028561:Transition Elements; D006108:Graphite