Electronic spin transport in graphene field-effect transistors

By M. Popinciuc, C. Jozsa, P. Zomer, N. Tombros, A. Veligura, H. Jonkman, Van Wees. 2009

175 citations recorded by the source corpus.

Spin transport experiments in graphene, a single layer of carbon atoms ordered in a honeycomb lattice, indicate spin-relaxation times that are significantly shorter than the theoretical predictions. We investigate experimentally whether these short spin-relaxation times are due to extrinsic factors, such as spin relaxation caused by low impedance contacts, enhanced spin-flip processes at the device edges, or the presence of an aluminum oxide layer on top of graphene in some samples. Lateral spin valve devices using a field-effect transistor geometry allowed for the investigation of the spin relaxation as a function of the charge density, going continuously from metallic hole to electron conduction (charge densities of n similar to 10(12) cm(-2)) via the Dirac charge neutrality point (n similar to 0). The results are quantitatively described by a one-dimensional spin-diffusion model where the spin relaxation via the contacts is taken into account. Spin valve experiments for various injector-detector separations and spin precession experiments reveal that the longitudinal (T-1) and the transversal (T-2) relaxation times are similar. The anisotropy of the spin-relaxation times tau and tau(perpendicular to), when the spins are injected parallel or perpendicular to the graphene plane, indicates that the effective spin-orbit fields do not lie exclusively in the two-dimensional graphene plane. Furthermore, the proportionality between the spin-relaxation time and the momentum-relaxation time indicates that the spin-relaxation mechanism is of the Elliott-Yafet type. For carrier mobilities of 2x10(3)-5x10(3) cm(2)/V s and for graphene flakes of 0.1-2 mu m in width, we found spin-relaxation times on the order of 50-200 ps, times which appear not to be determined by the extrinsic factors mentioned above.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/5627f8585ead7a5c5f7262a1c249ca2c8716cfdb

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The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

  1. Hector Ochoa
  2. Jianhao Chen
  3. M. Fuhrer
  4. Francisco Guinea
  5. I. Vera-Marun
  6. Ahmet Avsar
  7. J. V. Wees
  8. B. Özyilmaz

In Electrical and Electronic Engineering

  1. I. Vera-Marun
  2. Hector Ochoa
  3. M. Fuhrer
  4. Ahmet Avsar
  5. J. V. Wees
  6. B. Özyilmaz
  7. Jianhao Chen
  8. Francisco Guinea

In Materials Chemistry

  1. M. Fuhrer
  2. Hector Ochoa
  3. Francisco Guinea
  4. Jianhao Chen
  5. I. Vera-Marun
  6. B. Özyilmaz
  7. N. M. R. Peres
  8. E. Hwang

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