Diluted Graphene Antiferromagnet

Brey, L.; Fertig, H. A.; Sarma, S. Das

doi:10.1103/physrevlett.99.116802

Cited by 272 publications

(320 citation statements)

References 27 publications

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“…32 The sublattice degree of freedom plays a central role in the magnetic properties of bipartite lattices. [33][34][35] Very much like an external magnetic field favors one spin orientation and splits the spin states, an external perturbation favors one sublattice with respect to the other and opens a gap in the band structure of graphene. 2,36 When this happens, it is not obvious a priori what happens to the edge states, even at the single particle level, and the associated magnetism.…”

Section: Introductionmentioning

confidence: 99%

Interplay between sublattice and spin symmetry breaking in graphene

Soriano

Fernández-Rossier

2012

Phys. Rev. B

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We study the effect of sublattice symmetry breaking on the electronic, magnetic, and transport properties of two-dimensional graphene as well as zigzag terminated one-and zero-dimensional graphene nanostructures. The systems are described with the Hubbard model within the collinear mean field approximation. We prove that for the noninteracting bipartite lattice with an unequal number of atoms in each sublattice, in-gap states still exist in the presence of a staggered on-site potential ± /2. We compute the phase diagram of both 2D and 1D graphene with zigzag edges, at half filling, defined by the normalized interaction strength U/t and /t, where t is the first neighbor hopping. In the case of 2D we find that the system is always insulating, and we find the U c ( ) curve above which the system goes antiferromagnetic. In 1D we find that the system undergoes a phase transition from nonmagnetic insulator for U < U c ( ) to a phase with ferromagnetic edge order and antiferromagnetic interedge coupling. The conduction properties of the magnetic phase depend on and can be insulating, conducting, and even half-metallic, yet the total magnetic moment in the system is zero. We compute the transport properties of a heterojunction with two magnetic graphene ribbon electrodes connected to a finite length armchair ribbon and we find a strong spin filter effect.

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Section: Introductionmentioning

confidence: 99%

Interplay between sublattice and spin symmetry breaking in graphene

Soriano

Fernández-Rossier

2012

Phys. Rev. B

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“…The fact that σ 0 scales with W/L to a value slightly smaller than 4e 2 /πh for W/L → ∞ 24 can, in principle, be attributed to the chosen electrode model. One could possibly improve this result, i.e., increase the conductivity closer to the universal value 4e 2 /πh, by tuning the tight-binding parameters of the Bethe lattice or by using a different model for the electrodes 24,25 . Whether or not the LDA minimal conductivity of clean graphene can reach the universal value 4e 2 /πh is, anyhow, not essential in the ensuing discussion.…”

Section: Conductivity Resultsmentioning

confidence: 99%

Origin of the quasiuniversality of the minimal conductivity of graphene

Palacios

2010

Phys. Rev. B

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It is a fact that the minimal conductivity σ0 of most graphene samples is larger than the wellestablished universal value for ideal graphene 4e 2 /πh; in particular, larger by a factor > ∼ π. Despite intense theoretical activity, this fundamental issue has eluded an explanation so far. Here we present fully atomistic quantum mechanical estimates of the graphene minimal conductivity where electronelectron interactions are considered in the framework of density functional theory. We show the first conclusive evidence of the dominant role on the minimal conductivity of charged impurities over ripples, which have no visible effect. Furthermore, in combination with the logarithmic scaling law for diffusive metallic graphene, we ellucidate the origin of the ubiquitously observed minimal conductivity in the range 8e 2 /h > σ0 > ∼ 4e 2 /h.

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“…The dispersion of δ for a fixed total magnetization M T is the outcome of indirect exchange coupling. 18 For comparison with the experiments, it is worth considering two extreme magnetic landscapes. At large external field, all the magnetic moments are aligned, i.e., m z (i) = +1.…”

Section: B Relevant Energy Scalesmentioning

confidence: 99%

Graphene single-electron transistor as a spin sensor for magnetic adsorbates

2013

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We study single-electron transport through a graphene quantum dot with magnetic adsorbates. We focus on the relation between the spin order of the adsorbates and the linear conductance of the device. The electronic structure of the graphene dot with magnetic adsorbates is modeled through numerical diagonalization of a tight-binding model with an exchange potential. We consider several mechanisms by which the adsorbate magnetic state can influence transport in a single-electron transistor: tuning the addition energy, changing the tunneling rate, and in the case of spin-polarized electrodes, through magnetoresistive effects. Whereas the first mechanism is always present, the others require that the electrode has to have either an energy-or spin-dependent density of states. We find that graphene dots are optimal systems to detect the spin state of a few magnetic centers.

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Diluted Graphene Antiferromagnet

Cited by 272 publications

References 27 publications

Interplay between sublattice and spin symmetry breaking in graphene

Interplay between sublattice and spin symmetry breaking in graphene

Origin of the quasiuniversality of the minimal conductivity of graphene

Graphene single-electron transistor as a spin sensor for magnetic adsorbates

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