Imaging coherent transport in a mesoscopic graphene ring

Cabosart, Damien; Faniel, Sébastien; Martins, Frederico Rodrigues; Brun, Boris; Felten, Alexandre; Bayot, Vincent; Hackens, Benoît

doi:10.1103/physrevb.90.205433

Cited by 30 publications

(38 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Strikingly, the maximum visibility 38 is found close to the charge neutrality point at V G = 3 V and is around 0.25% with respect to the overall conductance G 2W . Although the maximum twoterminal visibility is similar to earlier experiments on diffusive graphene rings, 18,22 the carrier density dependency is inverted. For example, in contrast to Ref.…”

Section: Methodssupporting

confidence: 86%

Aharonov-Bohm oscillations and magnetic focusing in ballistic graphene rings

et al. 2017

View full text Add to dashboard Cite

We present low-temperature magnetotransport measurements on graphene rings encapsulated in hexagonal boron nitride. We investigate phase-coherent transport and show Aharonov-Bohm (AB) oscillations in quasi-ballistic graphene rings with hard confinement. In particular, we report on the observation of h/e, h/2e and h/3e conductance oscillations. Moreover we show signatures of magnetic focusing effects at small magnetic fields confirming ballistic transport. We perform tight binding calculations which allow to reproduce all significant features of our experimental findings and enable a deeper understanding of the underlying physics. Finally, we report on the observation of the AB conductance oscillations in the quantum Hall regime at reasonable high magnetic fields, where we find regions with enhanced AB oscillation visibility with values up to 0.7%. These oscillations are well explained by taking disorder into account allowing for a coexistence of hard and soft-wall confinement.

show abstract

Section: Methodssupporting

confidence: 86%

Aharonov-Bohm oscillations and magnetic focusing in ballistic graphene rings

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Starting from the seminal study of Aharonov and Bohm [35] the influence of distant electromagnetic potential on quantum particle propagation has been utilized in numerous works to research coherent transport in mesoscopic structures (see e.g. [36][37][38]). The Aharonov-Bohm (AB) effect in different geometries is actively employed to investigate the MBS features as well.…”

Section: Introductionmentioning

confidence: 99%

Fano effect in Aharonov–Bohm ring with topologically superconducting bridge

Вальков¹,

Kagan²,

Aksenov³

2019

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Taking into account an inner structure of the arms of the Aharonov-Bohm ring (AB ring) we have analyzed the transport features related to the topological phase transition which is induced in a superconducting wire (SC wire) with strong spin-orbit interaction (SOI). The SC wire acts as a bridge connecting the arms. The in-plane magnetic-field dependence of linear-response conductance obtained using the nonequilibrium Green's functions in the tight-binding approximation revealed the Breit-Wigner and Fano resonances (FRs) if the wire is in the nontrivial phase. The effect is explained by the presence of two interacting transport channels in the system. As a result, the FRs are attributed to bound states in continuum (BSCs). The BSC lifetime is determined by both hopping parameters between subsystems and the SC-wire properties. It is established that the FR width and position are extremely sensitive to the type of the lowest-energy excitation in the SC wire, the Majorana or Andreev bound state (MBS or ABS, respectively). Moreover, it is shown that in the specific case of the AB ring, the T-shape geometry, the FR disappears for the transport via the MBS and the conductance is equal to one quantum. It doubles in the local transport regime. On the contrary, in the ABS case the local conductance vanishes. The influence of the mean-field Coulomb interactions and diagonal disorder in the SC wire on the FR is investigated.

show abstract

“…Graphene [1] as a chiral Dirac conductor with mean free path [2,3] and coherence length [4] of up to several micrometers is an excellent medium for studies of electron optics [5][6][7][8][9] and formation of electron interferometers [10][11][12][13][14][15][16][17][18]. This gapless material can be doped electrostatically with the external gates setting the Fermi energy above or below the Dirac point.…”

Section: Introductionmentioning

confidence: 99%

Aharonov-Bohm conductance oscillations and current equilibration in local n−p junctions in graphene

2018

View full text Add to dashboard Cite

We consider a small p-type island defined within n-type graphene nanoribbon induced by potential of a floating electrode. In the quantum Hall conditions the island supports persistent currents localized at the n − p junction. When coupled to the graphene edge the island acts as an Aharonov-Bohm interferometer. We evaluate the electrostatic potential induced by the floating gate within the ribbon near the charge neutrality point and consider equilibration of the currents at both sides of the junction. The incoherent equilibration is introduced by the virtual probes technique. We describe the evolution of the coherent Aharonov-Bohm conductance oscillations to the quantum Hall fractional plateaus due to the current equilibration.

show abstract

Imaging coherent transport in a mesoscopic graphene ring

Abstract: International audienc

Cited by 30 publications

References 55 publications

Aharonov-Bohm oscillations and magnetic focusing in ballistic graphene rings

Aharonov-Bohm oscillations and magnetic focusing in ballistic graphene rings

Fano effect in Aharonov–Bohm ring with topologically superconducting bridge

Aharonov-Bohm conductance oscillations and current equilibration in local n−p junctions in graphene

Contact Info

Product

Resources

About