Stable local moments of vacancies, substitutional and hollow site impurities in graphene

Mashkoori, Mahdi; Jafari, S A

doi:10.1088/0953-8984/27/15/156001

Cited by 6 publications

(6 citation statements)

References 33 publications

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“…The magnetic phase diagram of the adatom on graphene has been intensively studied [13,[27][28][29][30]. With proper parameters, the adatom will become magnetic with n ↑ = n ↓ .…”

mentioning

confidence: 99%

Hydrogen-induced magnetism in graphene: a simple effective model description

Li,

Yu,

Gao

et al. 2019

Preprint

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Hydrogen adatoms induced magnetic moment on graphene has been observed in atomic scale in a recent experiment [González-Herrero et al., Science 352, 437 (2016)]. Here, we demonstrate that all the experimental phenomena can be simply and well described by an equivalent Anderson impurity model, where the electronic correlations on both carbon and hydrogen atoms are represented by an effective on-site Coulomb interaction on hydrogen adatom UH . This simple equivalent model works so well is because that the main effect of Coulomb interaction on both carbon and hydrogen atoms is just to split the impurity resonance states with different spin. This effective Anderson impurity model can also well reproduce all the behaviours of hydrogen dimer on graphene observed in experiment. We thus argue that it should be a general model to describe the hydrogen adatoms on graphene with various adsorption configurations, especially for their magnetic properties.

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“…The magnetic phase diagram of the adatom on graphene has been intensively studied [13,[27][28][29][30]. With proper parameters, the adatom will become magnetic with n ↑ = n ↓ .…”

mentioning

confidence: 99%

Hydrogen-induced magnetism in graphene: a simple effective model description

Li,

Yu,

Gao

et al. 2019

Preprint

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“…We would like to compare the situations of the monolayer 14,15,17 and bilayer graphene 38,[53][54][55] with the case of TLG we studied here. The DOS of the undoped monolayer graphene is zero at the Fermi level , so that the effective hybridization is nearly zero and the adatom prefers to be magnetic.…”

Section: Discussionmentioning

confidence: 99%

“…The adatom introduces many important physics to the graphene system, e.g. the modification of transport property [3][4][5][6] , the enhancement of spinorbit interaction [7][8][9][10][11][12][13] , the formation of local magnetic moment [14][15][16][17][18] , and the Kondo physics [19][20][21][22][23] . One most recent breakthrough is about the hydrogen atom absorbed on graphene, where the local magnetic moment of the hydrogen adatom is confirmed and manipulated in a scanning tunnelling microscopy (STM) experiment 18 , nearly ten years after its theoretical proposal.…”

Section: Introductionmentioning

confidence: 99%

Fano-shaped impurity spectral density, electric-field-induced in-gap state, and local magnetic moment of an adatom on trilayer graphene

Zhang

Lü

et al. 2017

Phys. Rev. B

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Recently, the existence of local magnetic moment in a hydrogen adatom on graphene has been confirmed experimentally [González-Herrero et al., Science, 2016, 352, 437]. Inspired by this breakthrough, we theoretically investigate the top-site adatom on trilayer graphene (TLG) by solving the Anderson impurity model via self-consistent mean field method. The influence of the stacking order, the adsorption site and external electric field are carefully considered. We find that, due to its unique electronic structure, the situation of the TLG is drastically different from that of the monolayer graphene. Firstly, the adatom on rhombohedral stacked TLG (r-TLG) can have a Fano-shaped impurity spectral density, instead of the normal Lorentzian-like one, when the impurity level is around the Fermi level. Secondly, the impurity level of the adatom on r-TLG can be tuned into an in-gap state by an external electric field, which strongly depends on the direction of the applied electric field and can significantly affect the local magnetic moment formation. Finally, we systematically calculate the impurity magnetic phase diagrams, considering various stacking orders, adsorption sites, doping and electric field. We show that, because of the in-gap state, the impurity magnetic phase of r-TLG will obviously depend on the direction of the applied electric field as well. All our theoretical results can be readily tested in experiment, and may give a comprehensive understanding about the local magnetic moment of adatom on TLG.

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“…Interest in graphene magnetism and its potential applications in spintronics started to grow soon after the isolation and characterization of this two-dimensional material [1][2][3][4][5][6][7][8][9]. One particularly intensively explored approach to making graphene magnetic is through point defects [10][11][12][13][14][15][16], such as adsorbing adatoms [17][18][19][20][21][22][23][24] and vacancies [25][26][27][28][29][30][31][32][33][34]. While transition metal adatoms with d or f electrons constitute an obvious option, rather amazingly, it has been shown both theoretically and experimentally that hydrogen impurities in graphene are also capable of inducing local magnetic moments [35][36][37][38][39][40][41][42], of the order of one Bohr magneton per defect.…”

Section: Introductionmentioning

confidence: 99%

Kondo effect due to a hydrogen impurity in graphene: A multichannel Kondo problem with diverging hybridization

2019

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We consider the Kondo effect arising from a hydrogen impurity in graphene. As a first approximation, the strong covalent bond to a carbon atom removes that carbon atom without breaking the C3 rotation symmetry, and we only retain the Hubbard interaction on the three nearest neighbors of the removed carbon atom which then behave as magnetic impurities. These three impurity spins are coupled to three conduction channels with definite helicity, two of which support a diverging local density of states (LDOS) ∝ 1/ |ω| ln 2 (Λ/ |ω|) near the Dirac point ω → 0 even though the bulk density of states vanishes linearly. We study the resulting 3-impurity multichannel Kondo model using the numerical renormalization group method. For weak potential scattering, the ground state of the Kondo model is a particle-hole symmetric spin-1/2 doublet, with ferromagnetic coupling between the three impurity spins; for moderate potential scattering, the ground state becomes a particle-hole asymmetric spin singlet, with antiferromagnetic coupling between the three impurity spins. This behavior is inherited by the Anderson model containing the hydrogen impurity and all four carbon atoms in its vicinity. arXiv:1907.05331v2 [cond-mat.str-el]

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Stable local moments of vacancies, substitutional and hollow site impurities in graphene

Cited by 6 publications

References 33 publications

Hydrogen-induced magnetism in graphene: a simple effective model description

Hydrogen-induced magnetism in graphene: a simple effective model description

Fano-shaped impurity spectral density, electric-field-induced in-gap state, and local magnetic moment of an adatom on trilayer graphene

Kondo effect due to a hydrogen impurity in graphene: A multichannel Kondo problem with diverging hybridization

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