Spin Control in Graphene Quantum Dots

SPIN CONTROL IN GRAPHENE QUANTUM DOTS
A. D. Güçlü

Institute for Microstructural Sciences, National Research Council of
Canada, Ottawa, Canada.

FASS 1096  " 8 June Wednesday 13:40 - 15:30 "

We predict theoretically electronic, magnetic, and optical properties of
graphene quantum dots using tight-binding, Hartree-Fock, DFT, and
configuration interaction calculations. We demonstrate that in triangular
quantum dots with zigzag edges [1], magnetic and optical properties are
dominated by strong electron-electron interactions as a function of the
filling factor of the zero energy states [2-5]. This allows to control the
spin [2] and optical properties [4] by an external gate. In bilayer
quantum dots[6], the spins of the two layers interact ferromagnetically.
By applying a vertical electric-field, the total spin of the bilayer
structure can be either turned off or reduced to a single localized spin.
Collaborators: P. Potasz, O. Voznyy, M. Korkusinski, and P. Hawrylak.

[1] J. Fernandez-Rossier and J. J. Palacios, Phys. Rev. Lett. 99, 177204
(2007).
[2] A. D. Güçlü, P. Potasz, O. Voznyy, M. Korkusinski, and P.  Hawrylak,
Phys. Rev. Lett. 103, 246805 (2009).
[3] P. Potasz, A. D. Güçlü, P. Hawrylak, Phys. Rev. B 81, 033403 (2010).
[4] A. D. Güçlü, P. Potasz, and P. Hawrylak, Phys. Rev. B 82, 155445 (2010).
[5] O. Voznyy, A. D. Güçlü, P. Potasz and  P. Hawrylak, Phys. Rev. B 83,
165417 (2011).
[6] A. D. Güçlü, P. Potasz, and P. Hawrylak. arXiv:1104.3108 (2011).

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Alev Devrim Guclu, PhD

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