Armchair graphene nanoribbons: Electronic structure and electric-field modulation

Raza, Hassan; Kan, Edwin C.

doi:10.1103/physrevb.77.245434

Cited by 207 publications

(181 citation statements)

References 32 publications

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“…Therefore, the electronic structure of GNRs can be engineered by modification of local structure of edge [103], altering GNR configuration (e.g. width and crystallographic orientation) [104,105] as well as electron–electron and spin–orbit interactions [59,106]. More detailed information about the design of electronic properties of GNRs was given by Dutta and Pati [107] and Yazyev et al [108].…”

Section: The Structure Of Graphenementioning

confidence: 99%

Structure of graphene and its disorders: a review

Gao

Lee

et al. 2018

Science and Technology of Advanced Materials

495

187

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Monolayer graphene exhibits extraordinary properties owing to the unique, regular arrangement of atoms in it. However, graphene is usually modified for specific applications, which introduces disorder. This article presents details of graphene structure, including sp2 hybridization, critical parameters of the unit cell, formation of σ and π bonds, electronic band structure, edge orientations, and the number and stacking order of graphene layers. We also discuss topics related to the creation and configuration of disorders in graphene, such as corrugations, topological defects, vacancies, adatoms and sp3-defects. The effects of these disorders on the electrical, thermal, chemical and mechanical properties of graphene are analyzed subsequently. Finally, we review previous work on the modulation of structural defects in graphene for specific applications.

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Section: The Structure Of Graphenementioning

confidence: 99%

Structure of graphene and its disorders: a review

Gao

Lee

et al. 2018

Science and Technology of Advanced Materials

495

187

View full text Add to dashboard Cite

show abstract

“…Based on a simple band structure calculation, we classify mod 0 and mod 1 aGNRs as semiconductors and mod 2 aGNRs as metals [125,126].…”

Section: Armchair Nanoribbonsmentioning

confidence: 99%

Theory of coherent phonons in carbon nanotubes and graphene nanoribbons

Sanders

Nugraha

Sato

et al. 2013

J. Phys.: Condens. Matter

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We survey our recent theoretical studies on the generation and detection of coherent radial breathing mode (RBM) phonons in single-walled carbon nanotubes and coherent radial breathing like mode (RBLM) phonons in graphene nanoribbons. We present a microscopic theory for the electronic states, phonon modes, optical matrix elements and electron-phonon interaction matrix elements that allows us to calculate the coherent phonon spectrum. An extended tight-binding (ETB) model has been used for the electronic structure and a valence force field (VFF) model has been used for the phonon modes. The coherent phonon amplitudes satisfy a driven oscillator equation with the driving term depending on the photoexcited carrier density. We discuss the dependence of the coherent phonon spectrum on the nanotube chirality and type, and also on the graphene nanoribbon mod number and class (armchair versus zigzag). We compare these results with a simpler effective mass theory where reasonable agreement with the main features of the coherent phonon spectrum is found. In particular, the effective mass theory helps us to understand the initial phase of the coherent phonon oscillations for a given nanotube chirality and type. We compare these results to two different experiments for nanotubes: (i) micelle suspended tubes and (ii) aligned nanotube films. In the case of graphene nanoribbons, there are no experimental observations to date. We also discuss, based on the evaluation of the electron-phonon interaction matrix elements, the initial phase of the coherent phonon amplitude and its dependence on the chirality and type. Finally, we discuss previously unpublished results for coherent phonon amplitudes in zigzag nanoribbons obtained using an effective mass theory.

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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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Armchair graphene nanoribbons: Electronic structure and electric-field modulation

Cited by 207 publications

References 32 publications

Structure of graphene and its disorders: a review

Structure of graphene and its disorders: a review

Theory of coherent phonons in carbon nanotubes and graphene nanoribbons

Graphene nanoribbons in criss-crossed electric and magnetic fields

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