Chemically induced large-gap quantum anomalous Hall insulator states in III-Bi honeycombs
| Autor: | Feng-Chuan Chuang, Christian P. Crisostomo, Hsin Lin, Chia-Hsiu Hsu, A. Bansil, Zhi-Quan Huang |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Band gap 02 engineering and technology Electronic structure Quantum Hall effect 01 natural sciences symbols.namesake 0103 physical sciences lcsh:TA401-492 General Materials Science 010306 general physics Quantum lcsh:Computer software Spintronics Condensed matter physics Fermi level 021001 nanoscience & nanotechnology Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Semimetal Computer Science Applications lcsh:QA76.75-76.765 Mechanics of Materials Modeling and Simulation Topological insulator symbols lcsh:Materials of engineering and construction. Mechanics of materials 0210 nano-technology |
| Zdroj: | npj Computational Materials, Vol 3, Iss 1, Pp 1-7 (2017) |
| ISSN: | 2057-3960 |
| Popis: | The search for novel materials with new functionalities and applications potential is continuing to intensify. Quantum anomalous Hall (QAH) effect was recently realized in magnetic topological insulators (TIs) but only at extremely low temperatures. Here, based on our first-principles electronic structure calculations, we predict that chemically functionalized III-Bi honeycombs can support large-gap QAH insulating phases. Specifically, we show that functionalized AlBi and TlBi films harbor QAH insulator phases. GaBi and InBi are identified as semimetals with non-zero Chern number. Remarkably, TlBi exhibits a robust QAH phase with a band gap as large as 466 meV in a buckled honeycomb structure functionalized on one side. Furthermore, the electronic spectrum of a functionalized TlBi nanoribbon with zigzag edge is shown to possess only one chiral edge band crossing the Fermi level within the band gap. Our results suggest that III-Bi honeycombs would provide a new platform for developing potential spintronics applications based on the QAH effect. Chemical functionalization could enable III-Bi honeycombs to host robust quantum anomalous Hall phases. The discovery of the Hall and anomalous Hall effects date back to the 19th Century, and their quantized versions are perhaps the best-known examples of topological electronic phases. The quantum anomalous Hall state draws special attention from an applications perspective, as it supports chiral edge states that are fully spin-polarised, which could be exploited for spintronics and low-power electronic devices. Its realization is currently restricted to very low temperatures, however. An international team of researchers led by Christian Crisostomo from National Sun Yat-Sen University use first-principles electronic structure calculations to predict that chemical functionalization could enable certain bismuth-based materials, which have a honeycomb lattice, to host robust quantum anomalous Hall phases, potentially at much higher temperatures. |
| Databáze: | OpenAIRE |
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