Graphene plasmons in nanostructured environments
Doktorsavhandling, 2017

This thesis explores the combination of electromagnetism with electrons in graphene. Graphene is a one atom thick layer of carbon atoms which contains electrons that exhibit rather special properties in terms of their conduction abilities. The combination of electromagnetism with electrons gives rise to new solutions to the governing equations --- solutions with characteristics not quite like normal electromagnetic radiation and not quite like electrons. These solutions, which also exist in normal conductors, are hybrids between electromagnetism and matter, and are usually referred to as plasmons. This thesis is a theoretical study of plasmons in graphene. Graphene plasmons are investigated by calculating the conductivity of graphene, starting from a Hamiltonian describing the low-energy graphene electrons. The conductivity is calculated using linear response theory in terms of Green's functions. In order to probe graphene plasmons with electromagnetic radiation, we consider a subwavelength dielectric grating as a coupling structure. We develop the necessary theory to calculate electromagnetic scattering from the combined system of graphene and grating. The techniques considered are a scattering matrix method and a finite element method. Both are applied to compute the scattering coefficients, which contain information about the graphene plasmons and are also obtainable in experiments. We use these techniques to study various aspects of graphene plasmons, such as their nonlocal properties and the effects of impurities. In addition, we examine the response of graphene plasmons to changes in the surrounding environment and apply this for sensing purposes. Finally, we show that graphene plasmons can be controlled using a DC current in the graphene sample.

subwavelength electromagnetic scattering

nonlocal response

Graphene plasmons

linear response Green's functions

Kollektorn (A423), MC2, Kemivägen 9
Opponent: Professor N. Asger Mortensen, Mads Clausen Institute, University of Southern Denmark, Odense


Tobias Wenger

Chalmers, Mikroteknologi och nanovetenskap (MC2), Tillämpad kvantfysik

High-sensitivity plasmonic refractive index sensing using graphene

2D Materials,; Vol. 4(2017)p. 25103-

Artikel i vetenskaplig tidskrift

Graphene plasmons in the presence of adatoms

New Journal of Physics,; Vol. 19(2017)p. Article no 073027 -

Artikel i vetenskaplig tidskrift

Optical signatures of nonlocal plasmons in graphene

Physical Review B: covering condensed matter and materials physics,; Vol. 94(2016)p. 205419-

Artikel i vetenskaplig tidskrift

Viola, G., Wenger, T., Kinaret, J., Fogelström, M. Graphene plasmons: impurities and nonlocal effects

Wenger, T., Viola, G., Kinaret, J. Fogelström, M., Tassin, P. Current-controlled light scattering and asymmetric plasmon propagation in graphene


Nanovetenskap och nanoteknik


Grundläggande vetenskaper


C3SE (Chalmers Centre for Computational Science and Engineering)


Den kondenserade materiens fysik



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4322


Chalmers tekniska högskola

Kollektorn (A423), MC2, Kemivägen 9

Opponent: Professor N. Asger Mortensen, Mads Clausen Institute, University of Southern Denmark, Odense