Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 48: Poster 2

HL 48.18: Poster

Thursday, March 26, 2009, 15:00–17:30, P2

Plasmons in graphene — •Antonio Hill, Sergey A. Mikhailov, and Klaus Ziegler — Institut für Physik, Universität Augsburg, D-86135 Augsburg, Germany

Electromagnetic response of graphene (the dielectric function) and the spectrum of collective excitations in it are studied as a function of wave vector and frequency. Our calculation is based on the full band structure, calculated within the tight-binding approximation. As a result, we find plasmons whose dispersion is similar to that obtained in the single-valley approximation [1,2] but in contrast to the latter, we find a stronger damping of the plasmon modes due to inter-band absorption. Our calculation also reveals effects due to deviations from the linear Dirac electronic spectrum as we increase the Fermi energy, indicating an anisotropic behavior with respect to the wave vector of the external electromagnetic field.

[1] E. H. Hwang and S. Das Sarma, 75, 205418 (2007)

[2] B. Wunsch et al, New J. Phys. 8, 318 (2006)