Orbital gyrotropic magnetoelectric effect and its strain engineering in monolayer 
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Bhowal, Sayantika; Satpathy, S.

doi:10.1103/physrevb.102.201403

Cited by 16 publications

(10 citation statements)

References 36 publications

(24 reference statements)

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“…This is expected to describe the system up to a maximum bias current I max = |E| max W/ρ ∼ 10 µA, corresponding to a maximum magnetization of 50 nA = 5400 µ B /µm 2 . The magnetoelectric effect considered in this work has been theoretically predicted in strained monolayer NbSe 2 [53] and TBG [26] and experimentally observed in strained monolayer MoS 2 [9,10]. Here we briefly compare the magnitude of the effect for these different materials assuming 0.5-1 % uniaxial tensile strain (see Ap-pendix C for details).…”

Section: A Magnitude Of the Effectmentioning

confidence: 83%

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Electrically tunable and reversible magnetoelectric coupling in strained bilayer graphene

Schaefer,

Nowack

2021

Preprint

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The valleys in hexagonal two-dimensional systems with broken inversion symmetry carry an intrinsic orbital magnetic moment. Despite this, such systems possess zero net magnetization unless additional symmetries are broken, since the contributions from both valleys cancel. A nonzero net magnetization can be induced through applying both uniaxial strain to break the rotational symmetry of the lattice and an in-plane electric field to break time-reversal symmetry owing to the resulting current. This creates a magnetoelectric effect whose strength is characterized by a magnetoelectric susceptibility, which describes the induced magnetization per unit applied in-plane electric field. Here, we predict the strength of this magnetoelectric susceptibility for Bernal-stacked bilayer graphene as a function of the magnitude and direction of strain, the chemical potential, and the interlayer electric field. We estimate that an orbital magnetization of 5400 µB/µm 2 can be achieved for 1 % uniaxial strain and a 10 µA bias current, which is almost three orders of magnitude larger than previously probed experimentally in strained monolayer MoS2. We also identify regimes in which the magnetoelectric susceptibility not only switches sign upon reversal of the interlayer electric field but also in response to small changes in the carrier density. Taking advantage of this reversibility, we further show that it is experimentally feasible to probe the effect using scanning magnetometry.

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Section: A Magnitude Of the Effectmentioning

confidence: 83%

“…A tight-binding model for strained monolayer NbSe 2 [53] predicts M z ∼ 10 4 µ B /µm 2 ∼ 10 −7 A for ε = 5 % and E = 10 4 V m −1 . Assuming a resistivity ρ ∼ 1 kΩ and device length L ∼ 10 µm, this corresponds to an approximate bias current I ∼ 100 µA and normalized magnetization M z /(Iε) ∼ 2 × 10 −4 A/(A %).…”

Section: Nbse2mentioning

confidence: 99%

Electrically tunable and reversible magnetoelectric coupling in strained bilayer graphene

Schaefer,

Nowack

2021

Preprint

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“…The OME describes the advent of an electrically induced orbital magnetization. Over the years it has received different names such as orbital Edelstein effect, kinetic magnetoelectric effect, orbital gyrotropic magnetoelectric effect (just to mention a few) that distinguish the mechanisms involved and characteristics of the systems where it occurs [11][12][13]. It has potential application for the development of data-storage orbitronic devices, and has been investigated in diverse materials [13][14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…In order to enable the appearance of the magnetoelectric effect, it is necessary to reduce its crystalline symmetry. One way of achieving this is by straining the material, as reported in references [38][39][40][41]. Here, however, we do it geometrically by considering nanoribbons with zigzag edges, which belong to the C 2v symmetry point group that allows nonzero values of α zx .…”

Section: Introductionmentioning

confidence: 99%

Orbital magnetoelectric effect in nanoribbons of transition metal dichalcogenides

Cysne¹,

Guimarães²,

Canonico³

et al. 2022

Preprint

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The orbital magnetoelectric effect (OME) generically refers to the appearance of an orbital magnetization induced by an applied electric field. Here, we show that nanoribbons of transition metal dichalcogenides (TMDs) with zigzag (ZZ) edges may exhibit a sizeable OME activated by an electric field applied along the ribbons' axis. We examine nanoribbons extracted from a monolayer (1L) and a bilayer (2L) of MoS2 in the trigonal (H) structural phase. Transverse profiles of the induced orbital angular momentum accumulations are calculated to first order in the longitudinally applied electric field. Our results show that close to the nanoribbon's edge-state crossings energy, the orbital angular momentum accumulations take place mainly around the ribbons' edges. They have two contributions: one arising from the orbital Hall effect (OHE) and the other consists in the OME. The former is transversely anti-symmetric with respect to the principal axis of the nanoribbon, whereas the latter is symmetric, and hence responsible for the resultant orbital magnetization induced in the system. We found that the orbital accumulation originating from the OHE for the 1L-nanoribbon is approximately half that of a 2L-nanoribbon. Furthermore, while the OME can reach fairly high values in 1L-TMD nanoribbons, it vanishes in the 2L ones that preserve spatial inversion symmetry.The microscopic features that justify our findings are also discussed.

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“…Interestingly, as shown in the example of gapped graphene, which we work out in detail below, VOHE does not even require the presence of spin-orbit coupling. Thus, we believe that gapped graphene, which is usually not considered a good candidate for spintronics applications due to weak spin-orbit effects [14,15], could play an important role in the context of efforts to control the orbital degrees of freedom of two-dimensional systems by electrical means [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Orbital Hall effect as an alternative to valley Hall effect in gapped graphene

Bhowal,

Vignale

2021

Preprint

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Gapped graphene has been proposed to be a good platform to observe the valley Hall effect, a transport phenomenon involving the flow of electrons that are characterized by different valley indices. In the present work, we show that this phenomenon is better described as an instance of the orbital Hall effect, where the ambiguous "valley" indices are replaced by a physical quantity, the orbital magnetic moment, which can be defined uniformly over the entire Brillouin zone. This description removes the arbitrariness in the choice of arbitrary cut-off for the valley-restricted integrals in the valley Hall conductivity, as the conductivity in the orbital Hall effect is now defined as the Brillouin zone integral of a new quantity, called the orbital Berry curvature. It is also more directly related to experimental observations of the effect.

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Orbital gyrotropic magnetoelectric effect and its strain engineering in monolayer NbX2

Cited by 16 publications

References 36 publications

Electrically tunable and reversible magnetoelectric coupling in strained bilayer graphene

Electrically tunable and reversible magnetoelectric coupling in strained bilayer graphene

Orbital magnetoelectric effect in nanoribbons of transition metal dichalcogenides

Orbital Hall effect as an alternative to valley Hall effect in gapped graphene

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