In:
physica status solidi (b), Wiley, Vol. 259, No. 4 ( 2022-04)
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 Bi 14 Rh 3 I 9 , the first weak 3D TI, topology presumably arises from stacking of the intermetallic [(Bi 4 Rh) 3 I] 2+ layers, which are predicted to be 2D TIs and to possess protected edge‐states, separated by topologically trivial [Bi 2 I 8 ] 2− octahedra chains. In the new layered salt Bi 12 Rh 3 Cu 2 I 5 , the same intermetallic layers are separated by planar, i.e., only one atom thick, [Cu 2 I 4 ] 2− anions. Density functional theory (DFT)‐based calculations show that the compound is a weak 3D TI, characterized by , 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., [(Bi 4 Rh) 3 I] 2+ and [Cu 2 I 4 ] 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.
Type of Medium:
Online Resource
ISSN:
0370-1972
,
1521-3951
DOI:
10.1002/pssb.202100447
Language:
English
Publisher:
Wiley
Publication Date:
2022
detail.hit.zdb_id:
208851-4
detail.hit.zdb_id:
1481096-7
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