Proximity-Induced Ferromagnetism in Graphene Revealed by the Anomalous Hall Effect

Wang, Zhiyong; Tang, Chi; Sachs, Raymond; Barlas, Yafis; Shi, Jing

doi:10.1103/physrevlett.114.016603

Cited by 511 publications

(527 citation statements)

References 34 publications

Supporting

Mentioning

508

Contrasting

Unclassified

Order By: Relevance

“…The QBE formalism that we have developed can also be extended to study the anomalous Hall effect in ferromagnetic graphene, for which the anomalous Hall conductivity receives a large extrinsic contribution 60 .…”

Section: Discussionmentioning

confidence: 99%

Direct coupling between charge current and spin polarization by extrinsic mechanisms in graphene

2016

View full text Add to dashboard Cite

Spintronics-the all-electrical control of the electron spin for quantum or classical information storage and processing-is one of the most promising applications of the two-dimensional material graphene. Although pristine graphene has negligible spin-orbit coupling (SOC), both theory and experiment suggest that SOC in graphene can be enhanced by extrinsic means, such as functionalization by adatom impurities. We present a theory of transport in graphene that accounts for the spin-coherent dynamics of the carriers, including hitherto-neglected spin precession processes taking place during resonant scattering in the dilute impurity limit. We uncover a novel "anisotropic spin precession" (ASP) scattering process in graphene, which contributes a large current-induced spin polarization and modifies the standard spin Hall effect. ASP scattering arises from two dimensionality and extrinsic SOC, and apart from graphene, it can be present in other 2D materials or in the surface states of 3D materials with a fluctuating SOC. Our theory also yields a comprehensive description of the spin relaxation mechanisms present in adatom-decorated graphene, including Elliot-Yafet and D'yakonov-Perel relaxation rates, the latter of which can become an amplification process in a certain parameter regime of the SOC disorder potential. Our work provides theoretical foundations for designing future graphene-based integrated spintronic devices.

show abstract

Section: Discussionmentioning

confidence: 99%

Direct coupling between charge current and spin polarization by extrinsic mechanisms in graphene

2016

View full text Add to dashboard Cite

show abstract

“…1,9-14 Experimentally, by employing ferromagnetic insulating substrates, AHE has been reported in graphene though much efforts are still required to realize the quantized version. [15][16][17][18] For such systems, a perpendicular magnetic field is usually required to align the magnetization of the system that prefers the in-plane orientation. This inspired us to think whether it is possible to realize QAHE by using inplane magnetization.…”

Section: Introductionmentioning

confidence: 99%

Quantum anomalous Hall effect in atomic crystal layers from in-plane magnetization

et al. 2016

View full text Add to dashboard Cite

We theoretically report that, with in-plane magnetization, the quantum anomalous Hall effect (QAHE) can be realized in two-dimensional atomic crystal layers with preserved inversion symmetry but broken out-of-plane mirror reflection symmetry. We take the honeycomb lattice as an example, where we find that the low-buckled structure, which makes the system satisfy the symmetric criteria, is crucial to induce QAHE. The topologically nontrivial bulk gap carrying a Chern number of C = ±1 opens in the vicinity of the saddle points M , where the band dispersion exhibits strong anisotropy. We further show that the QAHE with electrically tunable Chern number can be achieved in Bernalstacked multilayer systems, and the applied interlayer potential differences can dramatically decrease the critical magnetization to make the QAHE experimentally feasible.

show abstract

“…In the field of spintronics, graphene has exceptional charge transport properties but weak spin-orbit coupling (SOC) on the order of 10 µeV [8], which makes it ideal for long-distance spin transport [9][10][11] but ineffective for generating or manipulating spin currents. To advance towards spin manipulation, recent work has focused on heterostructures of graphene and magnetic insulators [12][13][14][15][16] or strong SOC materials such as transition metal dichalcogenides (TMDCs) and topological insulators [17][18][19]. The SOC induced in graphene by a TMDC could enable phenomena such as topological edge states [20] or the spin Hall effect [21][22][23].…”

mentioning

confidence: 99%

Giant Spin Lifetime Anisotropy in Graphene Induced by Proximity Effects

et al. 2017

View full text Add to dashboard Cite

We report on fundamental aspects of spin dynamics in heterostructures of graphene and transition metal dichalcogenides (TMDCs). By using realistic models derived from first principles we compute the spin lifetime anisotropy, defined as the ratio of lifetimes for spins pointing out of the graphene plane to those pointing in the plane. We find that the anisotropy can reach values of tens to hundreds, which is unprecedented for typical 2D systems with spin-orbit coupling and indicates a qualitatively new regime of spin relaxation. This behavior is mediated by spin-valley locking, which is strongly imprinted onto graphene by TMDCs. Our results indicate that this giant spin lifetime anisotropy can serve as an experimental signature of materials with strong spin-valley locking, including graphene/TMDC heterostructures and TMDCs themselves. Additionally, materials with giant spin lifetime anisotropy can provide an exciting platform for manipulating the valley and spin degrees of freedom, and for designing novel spintronic devices. [3,4], where the combined system might be engineered for specific applications [5] or might enable the exploration of new phenomena [6,7]. In the field of spintronics, graphene has exceptional charge transport properties but weak spin-orbit coupling (SOC) on the order of 10 µeV [8], which makes it ideal for long-distance spin transport [9-11] but ineffective for generating or manipulating spin currents. To advance towards spin manipulation, recent work has focused on heterostructures of graphene and magnetic insulators [12][13][14][15][16] or strong SOC materials such as transition metal dichalcogenides (TMDCs) and topological insulators [17][18][19]. The SOC induced in graphene by a TMDC could enable phenomena such as topological edge states [20] or the spin Hall effect [21][22][23].To this end, a variety of recent experiments have explored spin transport in graphene/TMDC heterostructures [21,[24][25][26][27][28][29]. Magnetotransport measurements revealed that graphene in contact with WS 2 exhibits a large weak antilocalization (WAL) peak, revealing a strong SOC induced by proximity effects [24][25][26]30]. Fits to the magnetoconductance yielded spin lifetimes τ s ≈ 5 ps, which is two to three orders of magnitude lower than graphene on traditional substrates [10,31]. It was later asserted that after the removal of a temperatureindependent background, τ s becomes at most only a few hundred femtoseconds [26]. Nonlocal Hanle measurements, meanwhile, have revealed spin lifetimes up to a few tens of picoseconds [27][28][29] that can be tuned by a back gate [28,29]. Finally, charge transport measure-

show abstract

Proximity-Induced Ferromagnetism in Graphene Revealed by the Anomalous Hall Effect

Cited by 511 publications

References 34 publications

Direct coupling between charge current and spin polarization by extrinsic mechanisms in graphene

Direct coupling between charge current and spin polarization by extrinsic mechanisms in graphene

Quantum anomalous Hall effect in atomic crystal layers from in-plane magnetization

Giant Spin Lifetime Anisotropy in Graphene Induced by Proximity Effects

Contact Info

Product

Resources

About