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Graphene: electrons in the flatland Antonio H. Castro Neto

Graphene: electrons in the flatland Antonio H. Castro Neto. Seoul, September 2008. Disclaimer. Andre Geim. Philip Kim. Kostya Novoselov. IQHE measured. Graphene is discovered. AHCN, P. Guinea, N. Peres, K. Novoselov, A. Geim, Rev. Mod. Phys. (2008). A brief history of graphene. 5 m m.

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Graphene: electrons in the flatland Antonio H. Castro Neto

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  1. Graphene: electrons in the flatlandAntonio H. Castro Neto Seoul, September 2008

  2. Disclaimer Andre Geim Philip Kim Kostya Novoselov IQHE measured Graphene is discovered AHCN, P. Guinea, N. Peres, K. Novoselov, A. Geim, Rev. Mod. Phys. (2008)

  3. A brief history of graphene

  4. 5 mm

  5. Au contacts SiO2 graphite Si Plus some nanotechnology… 2m • optical image • SEM image • design • contacts and mesa

  6. Some electronic properties of graphene t’ ~ 0.1 eV A t ~ 2.7 eV A B Next Nearest neighbors Nearest neighbors Unit cell

  7. In momentum space Dirac Cone Semi-Metal “Ultra relativistic” Solid State at low speed of light

  8. Novoselov et al, Science 306, 666 (2004)

  9. Vitor Pereira Nuno Peres Johan Nilsson Bruno Uchoa Valeri Kotov Outline • Coulomb impurity in graphene • Vitor M. Pereira, Johan Nilsson, AHCN • Phys.Rev.Lett. 99, 166802 (2007); • Vitor M. Pereira, Valeri Kotov, AHCN • Phys. Rev. B 78, 085101 (2008). • Anderson impurity in graphene • Bruno Uchoa, Valeri Kotov, Nuno Peres, AHCN • Phys. Rev. Lett. 101, 026805 (2008); • Bruno Uchoa, Chiung-Yuan Lin, Nuno Peres, AHCN • Phys.Rev.B 77, 035420 (2008)‏.

  10. Pereira et al., Phys.Rev.Lett. 99, 166802 (2007);

  11. Coupling 3D Schroedinger

  12. Undercritical Supercritical

  13. Andrei’s group

  14. HIC Neutron stars

  15. 1 nm

  16. E T>T K N(E) Anderson’s Impurity Model

  17. Non-interacting: U=0 V=0 Broadening Energy Energy

  18. Mean-Field

  19. U = 1 eV n_up n_down V=1eV, e0=0.2 eV The impurity moment can be switched on and off!

  20. U = 40 meV U = 0.1 eV

  21. Conclusions • Impurities in graphene behave in an unusual way when compared to normal metals and semiconductors. • One can test theories of nuclear matter under extreme conditions. • Control of the magnetic moment formation of transition metals using electric fields.

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