[Zurück]

L. Linhart:
"Electron scattering in graphene by accurately modeled lattice defects";
Betreuer/in(nen): F. Libisch, J. Burgdörfer; Institut für theoretische Physik 136, 2016; Abschlussprüfung: 23.11.2016.

Defects strongly influence the electronic properties of graphene. It is of
importance to get a deeper insight into the influence that defects have on electron
transport. In this work we accurately model defect structures with density
functional theory. We obtain tight-binding parameters via transforming the
results into the basis of maximally localized Wannier orbitals. We can then
treat large-scale structures with defects using a highly efficient tight-binding
approach. To combine the defect structure calculations with the surrounding
lattice, we present a new embedding technique that is applicable to a wide range
of zero-dimensional defects. This technique defines a transition region between
the tight-binding parameters of the bulk lattice and those obtained for the defect
structure. To test our technique we model an experimental setup currently
investigated at the University of Vienna.
Our approach turns out to be applicable to a broad range of defects. Calculations
were conducted for Stone-Wales defects, flower defects, double vacancies and
silicon substitutes. The scattering at these defects could be investigated in detail
for a wide range of energies. We find robust backscattering signatures of the
defect symmetries that can be explained by the band structure of graphene.

Graphene, quantum transport

http://publik.tuwien.ac.at/files/publik_256620.pdf