Dynamical Signatures of Edge-State Magnetism on Graphene Nanoribbons

Feldner, H.; Meng, Zi Yang; Lang, Thomas C.; Assaad, Fakher F.; Wessel, Stefan; Honecker, A.

doi:10.1103/physrevlett.106.226401

Cited by 129 publications

(108 citation statements)

References 31 publications

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“…A main conclusion of Ref. [83] was that the results from the two approaches agree with each other well in terms of the static properties. With respect to dynamic properties, the agreement holds but for narrow graphene ribbons.…”

Section: Conclusion and Discussionsupporting

confidence: 63%

“…Second, in Ref. [83], the dynamical properties of edge state magnetism in graphene systems were investigated. The results of static spin polarization from the mean-field theory were also compared with those from the quantum Monte Carlo (QMC) approach.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…There have been recent efforts in comparing the various aspects of the mean-field Hubbard model with those from first-principle or quantum Monte Carlo calculations, with the conclusion that the mean-field approximation is generally valid for graphene systems [80,81], especially in the weakly coupling regime [77,83]. It is thus justified to choose the parameter U below the critical Coulomb repulsion U c = 2.2t.…”

Section: A Mean-field Hubbard Hamiltonianmentioning

confidence: 99%

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Quantum chaotic tunneling in graphene systems with electron-electron interactions

et al. 2014

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An outstanding and fundamental problem in contemporary physics is to include and probe the many-body effect in the study of relativistic quantum manifestations of classical chaos. We address this problem using graphene systems described by the Hubbard Hamiltonian in the setting of resonant tunneling. Such a system consists of two symmetric potential wells separated by a potential barrier, and the geometric shape of the whole domain can be chosen to generate integrable or chaotic dynamics in the classical limit. Employing a standard mean-field approach to calculating a large number of eigenenergies and eigenstates, we uncover a class of localized states with near-zero tunneling in the integrable systems. These states are not the edge states typically seen in graphene systems, and as such they are the consequence of many-body interactions. The physical origin of the non-edge-state type of localized states can be understood by the one-dimensional relativistic quantum tunneling dynamics through the solutions of the Dirac equation with appropriate boundary conditions. We demonstrate that, when the geometry of the system is modified to one with chaos, the localized states are effectively removed, implying that in realistic situations where many-body interactions are present, classical chaos is capable of facilitating greatly quantum tunneling. This result, besides its fundamental importance, can be useful for the development of nanoscale devices such as graphene-based resonant-tunneling diodes.

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Section: Conclusion and Discussionsupporting

confidence: 63%

Section: Conclusion and Discussionmentioning

confidence: 99%

Section: A Mean-field Hubbard Hamiltonianmentioning

confidence: 99%

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Quantum chaotic tunneling in graphene systems with electron-electron interactions

et al. 2014

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“…A peak or a double-peak close to E F was observed in the local density of states (DOS) close to the edge with a peak distance scaling with the width of the GNR. The double-peak was present for chiral angles θ up to 16.1 • with respect to the zigzag direction and was ascribed to an antiferromagnetic coupling between opposite edges [16,31], as further evidenced by comparison with results from a Hubbard model Hamiltonian [16].…”

Section: Pacs Numbersmentioning

confidence: 76%

Electronic and Magnetic Properties of Zigzag Graphene Nanoribbons on the (111) Surface of Cu, Ag, and Au

Zhang

Morgenstern

et al. 2013

Phys. Rev. Lett.

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We have carried out an ab initio study of the structural, electronic and magnetic properties of zigzag graphene nanoribbons on Cu(111), Ag(111) and Au(111). Both, H-free and H-terminated nanoribbons are considered revealing that the nanoribbons invariably possess edge states when deposited on these surfaces. In spite of this, they do not exhibit a significant magnetization at the edge, with the exception of H-terminated nanoribbons on Au(111), whose zero-temperature magnetic properties are comparable to those of free-standing nanoribbons. These results are explained by the different hybridization between the graphene 2p orbitals and those of the substrates and, for some models, also by the charge transfer between the surface and the nanoribbon. Interestingly, H-free nanoribbons on Au(111) and Ag(111) exhibit two main peaks in the local density of states around the Fermi energy, which originate from different states and, thus, do not indicate edge magnetism. PACS numbers:Graphene [1] with its remarkable electronic and transport properties [2], in particular a high roomtemperature mobility [3], is a promising material for applications in information technology. While perfect monolayer graphene has a gapless spectrum prohibiting standard transistor applications, nanostructuring can induce the required band gap. Recent efforts focused on quasi one-dimensional graphene nanoribbons (GNRs) [4][5][6][7] and zero-dimensional graphene quantum dots (GQDs) [8][9][10]

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“…Graphene nanoribbons are quasi-one-dimensional structures with electronic properties depending on the angle at which they are cut. This includes a tunable energy gap with semimetallic or semiconductor behavior, [13][14][15] one-dimensional edge states at the Fermi level with unusual magnetic properties with possible spintronic applications, [16][17][18][19][20][21][22][23] and solitonic edge states as in polyacetylene. [37][38][39] Graphene nanoribbons also played an important role in inspiring the field of topological insulators.…”

Section: Introductionmentioning

confidence: 99%

Electron-electron interactions and topology in the electronic properties of gated graphene nanoribbon rings in Möbius and cylindrical configurations

2013

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We present a theory of the electronic properties of gated graphene nanoribbon rings with zigzag edges in Möbius and cylindrical configurations. The finite width opens a gap and nontrivial topology of the Möbius ring leads to a single edge with edge states with an induced, effective gauge field, in analogy to topological insulators. The single zigzag edge leads to a shell of degenerate states at the Fermi level and a ferromagnetic (FM) ground state at half-filling, i.e., at charge neutrality, due to electron-electron interactions. For fractional fillings, both the magnetic moment and the energy gap are found to oscillate as a function of the shell filling. In cylindrical rings, the two edges lead to AF ground state at half-filling but FM ground state at fractional fillings.

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Dynamical Signatures of Edge-State Magnetism on Graphene Nanoribbons

Cited by 129 publications

References 31 publications

Quantum chaotic tunneling in graphene systems with electron-electron interactions

Quantum chaotic tunneling in graphene systems with electron-electron interactions

Electronic and Magnetic Properties of Zigzag Graphene Nanoribbons on the (111) Surface of Cu, Ag, and Au

Electron-electron interactions and topology in the electronic properties of gated graphene nanoribbon rings in Möbius and cylindrical configurations

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