Quantum Transport in Graphene

Electron quantum optics in graphene

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Van der Waals heterostructures

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Quantum transport in the Terahertz range

When subjected to electromagnetic radiation, the fluctuation of the electronic current across a quantum conductor increases. This additional noise, called photon-assisted shot noise, arises from the generation and subsequent partition of electron-hole pairs in the conductor. The physics of photon-assisted shot noise has been thoroughly investigated at microwave frequencies up to 20 GHz, and its robustness suggests that it could be extended to the terahertz (THz) range. We have recently preformed present measurements of the quantum shot noise generated in a graphene nanoribbon subjected to a THz radiation. Our results show signatures of photon-assisted shot noise, further demonstrating that hallmark time-dependant quantum transport phenomena can be transposed to the THz range.

  • Photon-Assisted Shot Noise in Graphene in the Terahertz Range, F. D. Parmentier, L. N. Serkovic-Loli, P. Roulleau, and D. C. Glattli, Phys. Rev. Lett. 116, 227401 (2016)(arxiv)
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Scanning electron micrograph of a CVD-grown graphene ribbon connected to THz antennae-shaped electrodes.

Graphene Plasmonics

The chirality of the collective edge magnetoplasmon (EMP) waves in Graphene is evidenced and the cyclotron orbit drift velocity on Graphene edge determined.

Using an original picosecond pulses method we have measured the edge magnetoplasmon velocity in the QHE regime. This velocity is the sum of the EMP velocity due to Coulomb interaction and of the single particle carrier velocity, the so-called cyclotron orbit dirft velocity.

In the experiments, ~10ps electromagnetic pulses couple to the Graphene sample, propagate along its perimeter and the transmission is measured. The sample is a Graphene mono-layer from exfoliated natural graphite. The set-up can transmit microwaves up to 65 GHz in temperatures down to 2K and in a high magnetic field, up to 19.25 Tesla. The figure below shows different propagation time is observe for positive and negative field showing the chirality. The QHE manifests in plateaus in the propagation time for filling factor 2 and 6. Cyclotron drift velocity is found ~0.7 X Fermi velocity.

  • Edge magnetoplasmons in graphene, I Petkovic, F. I. B. Williams, and D. C. Glattli, Journal of Physics D, 47, 094010 (2014)(arxiv)
  • Carrier Drift Velocity and Edge Magnetoplasmons in Graphene, I. Petković, F. I. B. Williams, K. Bennaceur, F. Portier, P. Roche, and D. C. Glattli, Phys. Rev. Lett. 110, 016801 (2013), (arxiv)

Similar results have been obtained for SiC Graphene by N. Kumada et al at NTT Atsugi (Jpn) http://fr.arxiv.org/abs/1204.5034.

Recently, larger graphene sample from SiC wafer (collaboration NTT Japan) have allowed to measure de dispsersion relation and the decay rate of EMPs.

  • Resonant edge magnetoplasmons and their decay in graphene, N. Kumada, P. Roulleau, Benoît Roche, M. Hashisaka, H. Hibino, I. Petkovic, and D. C. Glattli, submitted **(arxiv)
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