Journal article
Blurring the Boundaries Between Topological and Nontopological Phenomena in Dots
Physical review letters, Vol.121(25), pp.256804-256804
12/21/2018
DOI: 10.1103/PhysRevLett.121.256804
PMID: 30608841
Abstract
We investigate the electronic and transport properties of topological and nontopological InAs0.85Bi0.15 quantum dots (QDs) described by a similar to 30 meV gapped Bernevig-Hughes-Zhang (BHZ) model with cylindrical confinement, i.e., "BHZ dots." Via modified Bessel functions, we analytically show that nontopological dots quite unexpectedly have discrete helical edge states, i.e., Kramers pairs with spinangular- momentum locking similar to topological dots. These unusual nontopological edge states are geometrically protected due to confinement for a wide range of parameters and remarkably contrast with the bulk-edge correspondence in topological insulators, as no bulk topological invariant guarantees their existence. Moreover, for a conduction window with four edge states, we find that the two-terminal conductance G versus the QD radius R and the gate Vg controlling its levels shows a double peak at 2e(2)/h for both topological and trivial BHZ QDs. This is in stark contrast to conductance measurements in 2D quantum spin Hall and trivial insulators. All of these results were also found in HgTe QDs. Bi-based BHZ dots should also prove important as hosts to room temperature edge spin qubits.
Details
- Title: Subtitle
- Blurring the Boundaries Between Topological and Nontopological Phenomena in Dots
- Creators
- Denis R. Candido - Universidade Federal de São CarlosMichael E. Flatte - University of IowaJ. Carlos Egues - Universidade de São Paulo
- Resource Type
- Journal article
- Publication Details
- Physical review letters, Vol.121(25), pp.256804-256804
- DOI
- 10.1103/PhysRevLett.121.256804
- PMID
- 30608841
- NLM abbreviation
- Phys Rev Lett
- ISSN
- 0031-9007
- eISSN
- 1079-7114
- Publisher
- Amer Physical Soc
- Number of pages
- 6
- Grant note
- CNPq; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) UFRN/MEC CAPES; Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) DMR-1420451 / Center for Emergent Materials, an NSF MRSEC; National Science Foundation (NSF) PRP-USP/Q-NANO FAPESP; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)
- Language
- English
- Date published
- 12/21/2018
- Academic Unit
- Electrical and Computer Engineering; Physics and Astronomy
- Record Identifier
- 9984428664302771
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