Journal article
Dual topological insulator with mirror symmetry protected helical edge states
Physical review. B, Vol.110(19), 195142
11/2024
DOI: 10.1103/PhysRevB.110.195142
Abstract
Dual topological insulators (DTIs) are simultaneously protected by time-reversal and crystal symmetries, representing advantageous alternatives to conventional topological insulators. By combining ab initio calculations and the 𝐤·𝐩 approach, here, we investigate the electronic band structure of a Na2CdSn triatomic layer and derive a low-energy 4×4 effective model consistent with all the symmetries of this material class. We obtain the effective Hamiltonian using the Löwdin perturbation theory, the folding-down technique, and the theory of invariants and determine its parameters by fitting our analytical dispersion relations to those of ab initio calculations. We then calculate the bulk topological invariants of the system and show that the Na2CdSn triatomic layer is a giant-gap (hundreds of millielectronvolts) quasi-two-dimensional DTI characterized by both spin and mirror Chern numbers −2. In agreement with the bulk-boundary correspondence theorem, we find that a finite-width strip of Na2CdSn possesses two pairs of counterpropagating helical edge states per interface. We obtain analytical expressions for the edge state energy dispersions and wave functions, which are shown to agree with our numerical calculations. Our work opens an avenue for further studies of Na2CdSn as a potential DTI candidate with room-temperature applications in areas of technological interest, such as nanoelectronics and spintronics.
Details
- Title: Subtitle
- Dual topological insulator with mirror symmetry protected helical edge states
- Creators
- Warlley H. Campos - Universidade de São PauloPoliana H. Penteado - Universidade de São PauloJulian Zanon - Eindhoven University of TechnologyPaulo E. Faria Junior - University of RegensburgDenis R. Candido - University of IowaJ. Carlos Egues - Universidade de São Paulo
- Resource Type
- Journal article
- Publication Details
- Physical review. B, Vol.110(19), 195142
- DOI
- 10.1103/PhysRevB.110.195142
- ISSN
- 2469-9950
- eISSN
- 2469-9969
- Publisher
- AMER PHYSICAL SOC
- Grant note
- National Council for Scientific and Technological Development (CNPq): 301595/2022-4, 152321/2020-9, 306122/2018-9 Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (PNPD/CAPES)Sao Paulo Research Foundation (FAPESP): 2020/00841-9, 956548 Deutsche Forschungsgemeinschaft (DFG, German Research Foundation): SFB 1277, 314695032, B07, B11 DFG-SPP: 2244, 443416183 Deutsche Forschungsgemeinschaft (DFG): TRR 173 268565370, A03
W.H.C. acknowledges helpful discussions with Michael Flatte and Jaroslav Fabian. This paper was supported by the National Council for Scientific and Technological Development (CNPq) Grant No. 301595/2022-4, PDJ Process No. 152321/2020-9, and Grant No. 306122/2018-9; by Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (PNPD/CAPES) ; by Sao Paulo Research Foundation (FAPESP) , Grant No. 2020/00841-9. J.Z. acknowledges the fi-nancial support of the Quantimony (Marie Sklodowska-Curie Project Grant No. 956548) . P.E.F.J. and W.H.C. acknowledge the financial support of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) SFB 1277 (Project-ID No. 314695032, Projects No. B07 and No. B11) . P.E.F.J. acknowledges the financial support of the DFG-SPP 2244 (Project No. 443416183) . W.H.C. acknowledges funding from the Deutsche Forschungsgemeinschaft (DFG) Grant No. TRR 173 268565370 (project A03) .
- Language
- English
- Date published
- 11/2024
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984752556102771
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