title: Correlation between topological band character and chemical bonding in a Bi14Rh3I9-based family of insulators.
abstract: Recently the presence of topologically protected edge-states in Bi14Rh3I9 was confirmed by scanning tunnelling microscopy consolidating this compound as a weak 3D topological insulator (TI). Here, we present a density-functional-theory-based study on a family of TIs derived from the Bi14Rh3I9 parent structure via substitution of Ru, Pd, Os, Ir and Pt for Rh. Comparative analysis of the band-structures throughout the entire series is done by means of a unified minimalistic tight-binding model that evinces strong similarity between the quantum-spin-Hall (QSH) layer in Bi14Rh3I9 and graphene in terms of Pz-molecular orbitals. Topologically non-trivial energy gaps are found for the Ir-, Rh-, Pt- and Pd-based systems, whereas the Os- and Ru-systems remain trivial. Furthermore, the energy position of the metal d-band centre is identified as the parameter which governs the evolution of the topological character of the band structure through the whole family of TIs. The d-band position is shown to correlate with the chemical bonding within the QSH layers, thus revealing how the chemical nature of the constituents affects the topological band character.
authors.affiliation: Department of Chemistry and Food Chemistry, TU Dresden, D-01062 Dresden, Germany.
authors.forename: Bertold
authors.initials: B
authors.lastname: Rasche
authors.affiliation: Department of Chemistry and Food Chemistry, TU Dresden, D-01062 Dresden, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Isaeva
authors.affiliation: Department of Chemistry and Food Chemistry, TU Dresden, D-01062 Dresden, Germany.|Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Ruck
authors.affiliation: Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany.|Dresden Center for Computational Materials Science (DCMS), TU Dresden, D-01069 Dresden, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Koepernik
authors.affiliation: Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany.|Dresden Center for Computational Materials Science (DCMS), TU Dresden, D-01069 Dresden, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Richter
authors.affiliation: Leibniz Institute for Solid State and Materials Research, IFW Dresden, D-01069 Dresden, Germany.|Dresden Center for Computational Materials Science (DCMS), TU Dresden, D-01069 Dresden, Germany.|Department of Physics, TU Dresden, D-01069 Dresden, Germany.
authors.forename: Jeroen
authors.initials: J
authors.lastname: van den Brink