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Bi14Rh3I9: Weak topology, crystal chemistry, and emerging functionalities
Madhav Prasad Ghimire1, Pradip Basnet1, Bishnu Belbase2
1Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, 44613, Nepal.
Summary
Bi14Rh3I9 is a novel weak three-dimensional topological insulator with insulating bulk and metallic boundary states. Further research is needed to confirm edge-channel conduction and address material defects for practical applications.
Area of Science:
- Condensed matter physics
- Materials science
- Solid-state physics
Background:
- Topological insulators (TIs) possess insulating bulk and conducting boundary states.
- Bi14Rh3I9 is the first identified weak 3D TI, built from 2D quantum spin Hall layers.
Purpose of the Study:
- To review advancements in Bi14Rh3I9 and its derivatives.
- To analyze material properties, synthesis, and characterization.
- To identify challenges and future directions for weak TIs.
Main Methods:
- Crystallographic analysis of its layered structure.
- Electronic structure calculations revealing a topological gap.
- Experimental validation using ARPES and STM.
Main Results:
- Bi14Rh3I9 exhibits a unique structure with intermetallic and insulating layers.
- A robust topological gap of ~210 meV is confirmed.
- 1D helical edge channels were observed experimentally.
Conclusions:
- Bi14Rh3I9 serves as a model system for weak topology.
- Key challenges include transport evidence, surface Fermi level, defects, and design rules.
- Addressing these is crucial for realizing TI functionalities.
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