Bi12Rh3Cu2I5: A 3D Weak Topological Insulator with Monolayer Spacers and Independent Transport Channels

Carrillo-Aravena E, Finzel K, Ray R, Richter M, Heider T, Cojocariu I, Baranowski D, Feyer V, Plucinski L, Gruschwitz M, Tegenkamp C, Ruck M (2022)

Publication Type: Journal article

Publication year: 2022

Journal

physica status solidi (b) Wiley

DOI: 10.1002/pssb.202100447

Abstract

Topological insulators (TIs) are semiconductors with protected electronic surface states that allow dissipation-free transport. TIs are envisioned as ideal materials for spintronics and quantum computing. In Bi14Rh3I9, the first weak 3D TI, topology presumably arises from stacking of the intermetallic [(Bi4Rh)3I]2+ layers, which are predicted to be 2D TIs and to possess protected edge-states, separated by topologically trivial [Bi2I8]2− octahedra chains. In the new layered salt Bi12Rh3Cu2I5, the same intermetallic layers are separated by planar, i.e., only one atom thick, [Cu2I4]2− anions. Density functional theory (DFT)-based calculations show that the compound is a weak 3D TI, characterized by (Formula presented.), and that the topological gap is generated by strong spin–orbit coupling (E g,calc. ∼ 10 meV). According to a bonding analysis, the copper cations prevent strong coupling between the TI layers. The calculated surface spectral function for a finite-slab geometry shows distinct characteristics for the two terminations of the main crystal faces ⟨001⟩, viz., [(Bi4Rh)3I]2+ and [Cu2I4]2−. Photoelectron spectroscopy data confirm the calculated band structure. In situ four-point probe measurements indicate a highly anisotropic bulk semiconductor (E g,exp. = 28 meV) with path-independent metallic conductivity restricted to the surface as well as temperature-independent conductivity below 60 K.

Involved external institutions

Forschungszentrum Jülich / Research Centre Jülich (FZJ) DE Germany (DE) Technische Universität Chemnitz DE Germany (DE) Technische Universität Dresden DE Germany (DE) Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e.V. (IFW) / Leibniz Institute for Solid State and Materials Research Dresden DE Germany (DE)

How to cite

APA:

Carrillo-Aravena, E., Finzel, K., Ray, R., Richter, M., Heider, T., Cojocariu, I.,... Ruck, M. (2022). Bi12Rh3Cu2I5: A 3D Weak Topological Insulator with Monolayer Spacers and Independent Transport Channels. physica status solidi (b). https://dx.doi.org/10.1002/pssb.202100447

MLA:

Carrillo-Aravena, Eduardo, et al. "Bi12Rh3Cu2I5: A 3D Weak Topological Insulator with Monolayer Spacers and Independent Transport Channels." physica status solidi (b) (2022).

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