Energy-gap modulations of graphene ribbons under external fields: A theoretical study

Ritter, C.; Makler, S. S.; Latgé, A.

doi:10.1103/physrevb.77.195443

Cited by 67 publications

(26 citation statements)

References 20 publications

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“…18 Edge states at a zigzag edge of graphene nanostructures has attracted an immense amount of attention recently. [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] These one-dimensional (1D) extended states, localized near the system edge, are zero-energy states of topological origin, and are the result of particle-hole symmetry. 35 The flatband nature of the edge states contributes to the large density of states in neutral zigzag graphene nanoribbons (GNRs) at the Fermi energy, and leads to localized magnetic structures at the zigzag edges.…”

Section: Introductionmentioning

confidence: 99%

Effects of edge potential on an armchair-graphene open boundary and nanoribbons

Chiu

Chu

2012

Phys. Rev. B

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Pseudospin flipping is found to be the key process leading to the formation of an edge-potential-induced edge state at an armchair-graphene open boundary and nanoribbons. At an open boundary, the edge potential U 0 is shown to turn on pseudospin-flipped (intravalley) scattering even though U 0 does not post an apparent breaking of the AB site (basis atoms) symmetry. For a valley-polarized incident beam, the interference between the pseudospin-conserving (intervalley) and -nonconserving (intravalley) processes in the scattering state leads to a finite out-of-plane pseudospin density. This two-wave feature in the evanescent regime leads to the formation of the edge state. The physical origin of the edge state is different from that for the Tamm states in semiconductors. For an armchair-graphene nanoribbon with a gapless energy spectrum, applying U 0 to both edges opens up an energy gap. Both edge states and energy gap opening exhibit distinct features in nanoribbon conductance.

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Section: Introductionmentioning

confidence: 99%

Effects of edge potential on an armchair-graphene open boundary and nanoribbons

Chiu

Chu

2012

Phys. Rev. B

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“…The latter is the basis for the proposed valley filters. The electron confinement in GNRs causes their properties to be quite sensitive to an applied electric (Novikov & Levitov 2006;Novikov 2007;Raza & Kan 2008) or magnetic (Brey & Fertig 2006;Perfetto et al 2007;Golizadeh-Mojarad et al 2008;Ritter et al 2008) field. These changes are reflected in measurable quantities such as the ballistic conductivity, local/joined density of states (LDOS, JDOS) and optical conductivity (Lyo & Huang 2004;Li et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Graphene nanoribbons in criss-crossed electric and magnetic fields

Roslyak

Gumbs

Huang

2010

Phil. Trans. R. Soc. A.

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Graphene nanoribbons (GNRs) in mutually perpendicular electric and magnetic fields are shown to exhibit dramatic changes in their band structure and electron-transport properties. A strong electric field across the ribbon induces multiple chiral Dirac points, closing the semiconducting gap in armchair GNRs. A perpendicular magnetic field induces partially formed Landau levels as well as dispersive surface-bound states. Each of the applied fields on its own preserves the even symmetry E k = E −k of the sub-band dispersion. When applied together, they reverse the dispersion parity to be odd, which gives E e,k = −E h,−k , and mix the electron and hole sub-bands within the energy range corresponding to the change in potential across the ribbon. This leads to oscillations of the ballistic conductance within this energy range. The broken time-reversal symmetry provides dichroism in the absorption of the circularly polarized light. As a consequence, one can observe electrically enhanced Faraday rotation, since the edges of the ribbon provide formation of the substantial density of states.

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“…We use Green function formalism and adopt real-space renormalization techniques, which properly incorporate local potential fluctuations. [15][16][17][18] The Hamiltonian reads…”

Section: Theorymentioning

confidence: 99%

Electron transport in quantum antidots made of four-terminal graphene ribbons

Ritter

Pacheco

Orellana

et al. 2009

Journal of Applied Physics

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Electronic and transport properties of two-and four-terminal graphene nanoribbons are studied taking into account different configurations of quantum antidot potentials, designed at a central conductor. Local density of states maps the electronic distribution changes induced by the antidot potentials and highlights localization effects at the neighboring vacancy sites. Depending on the position, extension, and symmetry of such antidots, we found delocalization of electronic states leading to particular conduction paths along the central region. The origin of dips and maxima in the conductance, and full transport suppression was studied within a microscopic scenario using real-space Green function formalism. The combination of antidot potentials and extra terminals in the device model has shown to generate a variety of transport responses that may be experimentally tuned.

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Energy-gap modulations of graphene ribbons under external fields: A theoretical study

Cited by 67 publications

References 20 publications

Effects of edge potential on an armchair-graphene open boundary and nanoribbons

Effects of edge potential on an armchair-graphene open boundary and nanoribbons

Graphene nanoribbons in criss-crossed electric and magnetic fields

Electron transport in quantum antidots made of four-terminal graphene ribbons

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