Experimental observation of edge magnetoplasma excitations in a two-dimensional electron system in the quantum-hall-effect regime

Khannanov, M. N.; Fortunatov, A. A.; Кукушкин, И. В.

doi:10.1134/s002136400922007x

Cited by 8 publications

(5 citation statements)

References 11 publications

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“…There have also been many studies on plasmons 15,16 and magnetoplasmons 17 , collective wave excitations, in unconfined graphene; for a re-view on plasmons and magnetoplasmons in conventional 2DES, e.g., see 18,19 . Different types of edge magnetoplasmons (EMPs) have been studied theoretically 18,[20][21][22][23][24][25][26][27] and experimentally [28][29][30] only for conventional 2DESs, see, e.g., Refs. 18,19 , and in particular Refs.…”

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confidence: 99%

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Edge magnetoplasmons in wide armchair graphene ribbons

2011

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We show that near an armchair edge of a wide graphene channel, and in the presence of a smooth step-like electrostatic lateral confining potential, the chirality, spectrum, spatial structure, and number of the fundamental edge magnetoplasmons (EMPs), in the ν = 2 regime of the quantum Hall effect, depend strongly on the position of the Fermi level EF . (i) When EF is small enough and intersects four degenerate states of the zero Landau level (LL) at one location and two degenerate states of this level at a different one, two fundamental, counter propagating EMPs exist with opposite chirality. This is in contrast with EMPs in conventional two-dimensional electron systems in which only one fundamental EMP exists. For the same wave vector these EMPs have different moduli of phase velocities and an essential spatial overlap. These EMPs can be on resonance in a wide range of frequencies, for micron or submicron lengths along the edge. (ii) When EF is sufficiently high and intersects only two degenerate states of the zero LL only one fundamental EMP exists with the usual chirality.

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“…18,19 , and in particular Refs. [28][29][30] for experimental studies of EMPs in the QHE regime. To our knowledge only the results of the EMP studies of Ref.…”

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Edge magnetoplasmons in wide armchair graphene ribbons

2011

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“…Different types of "density gradient" edge magnetoplasmons (EMPs) have been studied for (conventional) 2DES [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] subjected to a strong homogeneous magnetic field; for a discussion of previous publications, e.g., see [1]. These EMPs appear due to a strong change of the stationary local electron density at the edge of the channel (in particular, in the vicinity of edge states) that induces a strong modulation of the local magnetoconductivity tensor; modulation of the nondiagonal components is especially important [1,2,5,8,9,13].…”

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confidence: 99%

Spatial dispersion of magnetic-edge magnetoplasmons: Effect of semi-infinite gate

Balev¹,

Larkin²

2016

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Magnetic-edge magnetoplasmons (MEMPs) are obtained for a two-dimensional electron system (2DES) with atop semi-infinite metallic gate, at a distance d, and atop semi-infinite ferromagnetic film at a strong perpendicular magnetic field. For two most fast MEMPs, one with positive chirality and other with negative chirality, a strong spatial dispersion, due to effect of metallic half-plane gate, is obtained; some slower MEMPs manifest spatial dispersion too. Present MEMPs are localized at the magnetic-edge that is close to the wedge of metallic half-plane gate; the metallic wedge enhances localization of MEMPs at magnetic-edge. Obtained spatial dispersion has unconventional form. In particular, for two most fast MEMPs the phase velocities, ω/kx, are the linear polynomials on the wave vector kx in the long-wavelength region, kxd 1. Strong effect of the ferromagnetic film hysteresis on the MEMPs phase velocities and their anti-crossings are obtained for 0 < kxd ≤ 1. Two MEMPs of opposite chirality, especially two most fast MEMPs, at some resonance frequency can create a resonance circuit, with closed wave path along a fraction of the magnetic edge perimeter, with a total change of the wave phase given by an integer of 2π.

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“…This is in contrast with EMPs in conventional two-dimensional electron systems (2DES) which give only one fundamental EMP at the ν = 2 QHE regime, with negligible spin-splitting; for conventional 2DES different types of EMPs have been studied theoretically [17][18][19][20][21][22][23] and experimentally. [24][25][26] Above two counterpropagating EMPs can be on resonance if a strong coupling of the EMPs holds at the ends of the segment L em x ≤ L x , where L x is the length of graphene channel. 16 In present study for the case qualitatively outlined in Fig.…”

Section: Introductionmentioning

confidence: 99%

Edge magnetoplasmons in a wide armchair graphene ribbon with a weak superlattice potential: Finite-frequency gaps and zero group velocity

2012

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We show strong effects of a weak and smooth, on the magnetic length, superlattice potential upon edge magnetoplasmons (EMPs) at the armchair edge, with a smooth steplike electrostatic lateral confining potential, of a wide graphene channel in the ν = 2 quantum Hall effect regime. The superlattice potential leads to essential enlargement of a number of EMPs, descend from two fundamental EMPs in the absence of superlattice. For the wave vector kx within the first Brillouin zone, the EMPs show as the regions of acoustical or quasi-acoustical dispersion, with a finite value of group velocity, so the regions with frequency gaps, where a group velocity is nullified at some kx. We obtain that for kx → 0 only for two EMPs the frequency tends to zero as for other EMPs it obtains finite values. Strong dependence of dispersion relations of the EMPs from the period of the superlattice a0 and the distance d from a metallic gate is shown; in particular, for typical size of a gap, for characteristic value of the frequency and kx at which the group velocity is reduced to zero. At the frequency that corresponds to zero group velocity of pertinent fundamental EMP branch the response of the system should present a strong resonance.

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Experimental observation of edge magnetoplasma excitations in a two-dimensional electron system in the quantum-hall-effect regime

Cited by 8 publications

References 11 publications

Edge magnetoplasmons in wide armchair graphene ribbons

Edge magnetoplasmons in wide armchair graphene ribbons

Spatial dispersion of magnetic-edge magnetoplasmons: Effect of semi-infinite gate

Edge magnetoplasmons in a wide armchair graphene ribbon with a weak superlattice potential: Finite-frequency gaps and zero group velocity

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