Interaction-induced conductance from zero modes in a clean magnetic graphene waveguide

Cohnitz, Laura; Häusler, Wolfgang; Zazunov, Alex; Egger, Reinhold

doi:10.1103/physrevb.92.085422

Cited by 8 publications

(9 citation statements)

References 68 publications

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“…[52,53]. Let us also mention that in p-n-p or n-p-n devices, exotic non-Fermiliquid states are possible when electron-electron interactions between counterpropagating chiral interface states are taken into account [54,55]. However, for the p-n setups below, interaction effects are expected to be weak and will thus not be included.…”

Section: Introductionmentioning

confidence: 99%

Chiral interface states in graphene p−n junctions

et al. 2016

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We present a theoretical analysis of unidirectional interface states which form near p-n junctions in a graphene monolayer subject to a homogeneous magnetic field. The semiclassical limit of these states corresponds to trajectories propagating along the p-n interface by a combined skippingsnaking motion. Studying the two-dimensional Dirac equation with a magnetic field and an electrostatic potential step, we provide and discuss the exact and essentially analytical solution of the quantum-mechanical eigenproblem for both a straight and a circularly shaped junction. The spectrum consists of localized Landau-like and unidirectional snaking-skipping interface states, where we always find at least one chiral interface state. For a straight junction and at energies near the Dirac point, when increasing the potential step height, the group velocity of this state interpolates in an oscillatory manner between the classical drift velocity in a crossed electromagnetic field and the semiclassical value expected for a purely snaking motion. Away from the Dirac point, chiral interface states instead resemble the conventional skipping (edge-type) motion found also in the corresponding Schrödinger case. We also investigate the circular geometry, where chiral interface states are predicted to induce sizeable equilibrium ring currents.

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Section: Introductionmentioning

confidence: 99%

Chiral interface states in graphene p−n junctions

et al. 2016

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“…While early studies have focussed on the topological bound states of proximitized spinorbit coupled nanowires, more recent works have pointed out that in the presence of a superconducting coupling both topological and trivial bound states may exist [52][53][54][55][56][57][58][59][60][61][62][63]. Also, quite recently it has been realized that peculiar bound states can appear even when no superconducting coupling is present, if magnetic domains induce an inhomogeneous magnetic field on the nanowire [64], similarly to the magnetic confinement effects predicted in other materials [65][66][67].…”

Section: Introductionmentioning

confidence: 99%

Confinement versus interface bound states in spin-orbit coupled nanowires

2020

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Semiconductor nanowires with strong Rashba spin-orbit coupling are currently on the spotlight of several research fields such as spintronics, topological materials and quantum computation. While most theoretical models assume an infinitely long nanowire, in actual experimental setups the nanowire has a finite length, is contacted to metallic electrodes and is partly covered by gates. By taking these effects into account through an inhomogeneous spin-orbit coupling profile, we show that in general two types of bound states arise in the nanowire, namely confinement bound states and interface bound states. The appearance of confinement bound states, related to the finite length of the nanowire, is favoured by a mismatch of the bulk band bottoms characterizing the lead and the nanowire, and occurs even in the absence of magnetic field. In contrast, an interface bound states may only appear if a magnetic field applied perpendicularly to the spin-orbit field direction overcomes a critical value, and is favoured by an alignment of the band bottoms of the two regions across the interface. We describe in details the emergence of these two types of bound states, pointing out their differences. Furthermore, we show that when a nanowire portion is covered by a gate the application of a magnetic field can change the nature of the electronic ground state from a confinement to an interface bound state, determining a redistribution of the electron charge.

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“…Normally, for waveguides using a single conductor, no transverse-electromagnetic (TEM) mode could be transmitted. Most research focus on the transmission of the TE mode, while Cohnitz et al [32] investigated a magnetic graphene waveguide, in which a clean graphene is exposed to a static inhomogeneous magnetic field along one of the planar directions. As shown in Figure 4, when applying magnetic fields to a monolayer graphene, quantum modes exhibited like classical snake orbits near the field switch lines.…”

Section: Introductionmentioning

confidence: 99%

“…Schematic sketch of the MGW setup viewed from above. A magnetic field B is applied everywhere in the graphene plane except for the waveguide region |x| < d/2, where the field is reversed[32].…”

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confidence: 99%

Graphene Based Waveguides

Song¹,

Dai²,

Xiang³

2018

Emerging Waveguide Technology

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Graphene, which is well known as a one-atom thick carbon allotrope, has drawn lots of attention since its first announcement due to remarkable performance in mechanical, electrical, magnetic, thermal, and optical areas. In particular, unique properties of graphene such as low net absorption in broadband optical band, notably high nonlinear optical effects, and gate-variable optical conductivity make it an excellent candidate for high speed, high performance, and broadband electronic and photonics devices. Embedding graphene into optical devices longitudinally would enhance the light-graphene interaction, which shows great potential in photonic components. Since the carrier density of graphene could be tuned by external gate voltage, chemical doping, light excitation, graphene-based waveguide modulator could be designed to have high flexibility in controlling the absorption and modulation depth. Furthermore, graphene-based waveguides could take advantages in detection, sensing, polarizer, and so on.

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Interaction-induced conductance from zero modes in a clean magnetic graphene waveguide

Cited by 8 publications

References 68 publications

Chiral interface states in graphene p−n junctions

Chiral interface states in graphene p−n junctions

Confinement versus interface bound states in spin-orbit coupled nanowires

Graphene Based Waveguides

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