PhD Thesis

Wave packets in mesoscopic systems:
From time-dependent dynamics to transport phenomena in graphene and topological insulators

Viktor Krückl, Universit├Ątsverlag Regensburg (2013)
ISBN: 978-3-86845-097-2

At the beginning of 21th century, the range of solid state materials was extended by crystals featuring charge excitations with a chiral spin or pseudo-spin texture close to the Fermi energy. Such exceptional electronic properties can be found in graphene or topological insulators, which both render a great potential for upcoming electronic devices.

In this thesis, mesoscopic systems of such solid state materials are investigated by a time-dependent scheme, which describes the electronic excitations by the propagation of wave packets. Based on the time evolution of initial states dynamical and static observables are studied and new electronic phenomena are revealed. For example, the motion of electrons in graphene or topological insulators exhibit time-dependent features like Bloch-Zener oscillations or wave-packet revivals, which are not present in conventional electron gases. Also static properties, like transport characteristics, are encoded in the time evolution. For instance, the switching features of a topological insulator constriction can be extracted from a single wave-packet injected into a lead. The underlying effect builds the foundation of a novel charge and spin-transistor, which is presented in this thesis alongside other proposals for novel experiments in graphene or topological insulators.

Supporting material

Supporting online material for my PhD Thesis. Videos start to stream after clicking the pictures.

Zitterbewegung in Graphene

movie1a.flv (5 MB)                -              movie1b.flv (5 MB)

Wave-packet revivals in graphene

movie2.flv (20 MB)

Bloch-Zener oscillations

movie3.flv (2 MB)