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Paper   IPM / Physic / 12419
School of Physics
  Title:   Plasmons and Coulomb Drag in Dirac/Schroedinger Hybrid Electron Systems
1.  A. Principi
2.  M. Carrega
3.  R. Asgari
4.  V. Pellegrini
5.  M. Polini
  Status:   Published
  Journal: Phys. Rev. B (Editor's Suggestion)
  No.:  8
  Vol.:  86
  Year:  2012
  Pages:   085421
  Supported by:  IPM
We show that the plasmon spectrum of an ordinary two-dimensional electron gas (2DEG) hosted in a GaAs heterostructure is signi cantly modi ed when a graphene sheet is placed on the surface of the semiconductor in close proximity to the 2DEG. Long-range Coulomb interactions between massive electrons and massless Dirac fermions lead to a new set of optical and acoustic intra-subband plasmons. Here we compute the dispersion of these coupled modes within the Random Phase Approximation, providing analytical expressions in the long-wavelength limit that shed light on their dependence on the Dirac velocity and Dirac-fermion density. We also evaluate the resistivity in a Coulomb-drag transport setup. These Dirac/Schroedinger hybrid electron systems are experimentally feasible and open new research opportunities for fundamental studies of electron-electron interaction e ects in two spatial dimensions.

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