Helical edge states and edge-state transport in strained armchair graphene nanoribbons

Liu, Zhengfang; Wu, Qing‐Ping; Chen, Ai-Xi; Xiao, Xunwen; Liu, Nian-Hua; Miao, Guo‐Xing

doi:10.1038/s41598-017-08954-3

Cited by 9 publications

(3 citation statements)

References 57 publications

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“…However, strain is found to be a substantial parameter to tune the properties of topological insulators [26,27,[35][36][37][38][39][40] and to induce helical edge states in armchair graphene nanoribbon [42]. Contrary to the chiral edge modes, occurring in systems with broken TRS, the helical edge states appear in systems where TRS is preserved, as in QSH effect [13].…”

Section: Introductionmentioning

confidence: 99%

Strain tuned topology in the Haldane and the modified Haldane models

Mannaï

Haddad

2020

J. Phys.: Condens. Matter

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We study the interplay between a uniaxial strain and the topology of the Haldane and the modified Haldane models which, respectively, exhibit chiral and antichiral edge modes. The latter were, recently, predicted by Colomés and Franz (Phys. Rev. Lett. 120, 086603 (2018)) and expected to take place in the transition metal dichalcogenides. Using the continuum approximation and a tight-binding approach, we investigate the effect of the strain on the topological phases and the corresponding edge modes. We show that the strain could induce transitions between topological phases with opposite Chern numbers or tune a topological phase into a trivial one. As a consequence, the dispersions of the chiral and antichiral edge modes are found to be strain dependent. The strain may reverse the direction of propagation of these modes and eventually destroy them. This effect may be used for strain-tunable edge currents in topological insulators and two-dimensional transition metal dichalcogenides.

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Section: Introductionmentioning

confidence: 99%

Strain tuned topology in the Haldane and the modified Haldane models

Mannaï

Haddad

2020

J. Phys.: Condens. Matter

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“…Here the pseudogauge potential is induced by the uniaxial strain. As a corollary, the pseudogauge potential is a finite and constant, which is defined as As ( r ) = As ( x ) = tβε (1 + σ ) 33 , and σ = 0.165 is the Poisson’s ratio of graphite, t is the nearest-neighbour hopping parameter, and ε is the tensile strain. The constant β = ∂ lnt /∂ lnδ , where δ is the distance between nearest carbon atoms.…”

Section: Introductionmentioning

confidence: 99%

Tunable Dirac points and high spin polarization in ferromagnetic-strain graphene superlattices

Liu

Chen

et al. 2017

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Spin-dependent energy bands and transport properties of ferromagnetic-strain graphene superlattices are studied. The high spin polarization appears at the Dirac points due to the presence of spin-dependent Dirac points in the energy band structure. A gap can be induced in the vicinity of Dirac points by strain and the width of the gap is enlarged with increasing strain strength, which is beneficial for enhancing spin polarization. Moreover, a full spin polarization can be achieved at large strain strength. The position and number of the Dirac points corresponding to high spin polarization can be effectively manipulated with barrier width, well width and effective exchange field, which reveals a remarkable tunability on the wavevector filtering behavior.

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“…. For the future we will also continue to study graphene devices and nanostructures with the same purpose, since helical states were theoretically predicted [167] [168] and QSHE [169] and magnetic edge states [170] were recently observed in graphene devices.…”

Section: Discussionmentioning

confidence: 97%

Fabrication and characterization of Quantum Materials: Graphene heterostructures and Topological Insulators

Clericò¹

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Fabrication and characterization of Quantum Materials: Graphene heterostructures and Topological Insulators by Vito CLERICÒ Starting from a detailed description of the Clean Room facilities, installed during this thesis work, we report the fabrication processes based on graphene and other 2D materials in detail. In hBN-encapsulated graphene the Quantum Hall Effect (QHE) at room temperature and high magnetic field was observed. We found different features in the QHE respect a previous work on lower mobility graphene on silicon oxide (Novoselov et al. Science 315 1379 2007). A detalied study of transport properties in graphene nanoconstrictions is also reported. In particular in encapsulated graphene we introduced a new cryo-etching method to obtain low roughness edges nanocostrictions, in which quantized conductance was observed. In the last part of the thesis we report transport measurements on InAs/GaSb double quantum wells with different bandgap configurations (inverted, normal or critical). v Contents Acknowledgements v

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Helical edge states and edge-state transport in strained armchair graphene nanoribbons

Cited by 9 publications

References 57 publications

Strain tuned topology in the Haldane and the modified Haldane models

Strain tuned topology in the Haldane and the modified Haldane models

Tunable Dirac points and high spin polarization in ferromagnetic-strain graphene superlattices

Fabrication and characterization of Quantum Materials: Graphene heterostructures and Topological Insulators

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