Correlation between topological band character and chemical bonding in a $\mathbf{B}{\mathbf{i}}_{14}\mathbf{R}{\mathbf{h}}_3{\mathbf{I}}_9$-based family of insulators

Abstract

Recently the presence of topologically protected edge-states in Bi${}_{14}$Rh${}_3$I${}_9$ 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 Bi${}_{14}$Rh${}_3$I${}_9$ 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 Bi${}_{14}$Rh${}_3$I${}_9$ and graphene in terms of $p_z$-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.

References in corpus (3)

• Stacked topological insulator built from bismuth-based graphene sheet analogues
• Sub-nm wide electron channels protected by topology
• Existence, character and origin of surface-related bands in the high temperature iron pnictide superconductor BaFe_{2-x}Co_{x}As_{2}

Cited by in corpus (3)

• Chemical Gating of a Weak Topological Insulator: Bi14Rh3I9
• Nontrivial gapless electronic states at the stacking faults of weak topological insulators
• Strong and Weak Three-Dimensional Topological Insulators Probed by Surface Science Methods