Dilute magnetism in graphene

Sousa, Frederico J.; Amorim, B.; Castro, Eduardo V.

doi:10.48550/arxiv.1901.08614

Cited by 4 publications

(5 citation statements)

References 72 publications

(107 reference statements)

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“…We now move on to consider the case of vacancy effects [47][48][49][50][51][52][53][54][55] , namely, w → ∞. This limit is especially attractive because it can be achieved by adsorbed hydrogen atoms 56 .…”

Section: The Vacancy Limitmentioning

confidence: 99%

“…4 (a) and (b) show that interactions drive the system into an insulating state with antiferromagnetic order in the AA regions 45,61,67,68 . A more interesting scenario takes place in the presence of a vacancy in an AB region of TBG, in which case electronic interactions create a localized magnetic moment [47][48][49][50][51][52][53][54] . As shown in Figs.…”

Section: Interaction Effectsmentioning

confidence: 99%

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Impurity-induced triple point fermions in twisted bilayer graphene

Ramires

Lado

2019

Phys. Rev. B

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Triple point fermions are elusive electronic excitations that generalize Dirac and Weyl modes beyond the conventional high energy paradigm. Yet, finding real materials naturally hosting these excitations at the Fermi energy has remained challenging. Here we show that twisted bilayer graphene is a versatile platform to realize robust triple point fermions in two dimensions. In particular, we establish that the introduction of localized impurities lifts one of the two degenerate Dirac cones, yielding triple point fermions at charge neutrality. Furthermore, we show that the valley polarization is preserved for certain impurity locations in the moire supercell for both weak and strong impurity potentials. We finally show that in the presence of interactions, a symmetry broken state with local magnetization can develop out of the triple point bands, which can be selectively controlled by electrostatic gating. Our results put forward twisted bilayer graphene as a simple solid-state platform to realize triple point fermions at charge neutrality, and demonstrate the non-trivial role of impurities in moire systems.

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Section: The Vacancy Limitmentioning

confidence: 99%

Section: Interaction Effectsmentioning

confidence: 99%

Impurity-induced triple point fermions in twisted bilayer graphene

Ramires

Lado

2019

Phys. Rev. B

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“…Thus, on the intrinsic paramagnetic background, the spins easily form ferromagnetic couplings by a Ruderman− Kittel−Kasuya−Yosida (RKKY)-like 14 interaction through conduction electrons, which is similar to that reported in graphene, 48,49 resulting in the appearance of long-range ferromagnetic ordering. 50 Besides, to clarify the influence of different elements on the intrinsic electromagnetic properties of graphdiyne, the same calculations for oxygenated GDY and bromine-substituted GDY (BrsGDY) are also performed (Figures S17 and S18). Though the calculated local magnetic moments and DOS are similar to that of our synthesized substituted graphdiyne, the charge transfer caused by the carboxylate or Br atom is still much inferior to that in FsGDY (Table S2).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Induced Ferromagnetic Order of Graphdiyne Semiconductors by Introducing a Heteroatom

et al. 2020

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“…For the explicit form of V (2) s , see Appendix. To work with realistic impurities we consider hydrogen and fluorine adatoms, as both give sizable SOC enhancement [71,72] and can also carry magnetic moments [76,77,78,79,80,81,82,83]. Our methodology is standard: from H 0 at given µ we compute: 1) the eigenspectrum…”

Section: Model and Methodologymentioning

confidence: 99%

Spin relaxation and Yu-Shiba-Rusinov states in superconducting graphene

Kochan¹,

Barth²,

Costa³

et al. 2022

AIP Conference Proceedings

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We study theoretically the relaxation of quasi-particle spins in graphene in proximity to an s-wave superconductor in the presence of resonant magnetic and spin-orbit active impurities. It is well known that off resonance, the relaxation behaves as predicted from superconducting coherence: with lower temperatures the spin relaxation increases when electrons scatter off magnetic impurities (Hebel-Slichter effect), and decreases when the scatterers act via spin-orbit coupling. This distinct temperature dependence, not available in the normal state, can uniquely discriminate between the two scattering mechanisms. We have shown [1] that the Hebel-Slichter picture breaks down when magnetic impurities act resonantly-the emergent Yu-Shiba-Rusinov states inside the gap shift the spectral weight of the magnetic resonances and thus suppress their interaction with quasi-particle states. As a consequence this leads to a significant decrease of the spin-relaxation rate at lower temperatures. Our findings are valid for generic s-wave superconductors that host resonant magnetic impurities.

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Dilute magnetism in graphene

Cited by 4 publications

References 72 publications

Impurity-induced triple point fermions in twisted bilayer graphene

Impurity-induced triple point fermions in twisted bilayer graphene

Induced Ferromagnetic Order of Graphdiyne Semiconductors by Introducing a Heteroatom

Spin relaxation and Yu-Shiba-Rusinov states in superconducting graphene

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