Colloquium: December 3, 2014
How to Engineer the
Band Structure of a (Topological) Insulator?
|December 03, 2014 Wednesday||15:40||EE01|
Host: Balazs Hetenyi
ABSTRACT — Topological insulators represent unique phases of matter with insulating bulk and conducting edge or surface states, immune to small perturbations such as backscattering due to disorder. This stems from their peculiar band structure, which provides topological protections. Application-wise, topological insulators hold the promise to revolutionize spintronics, and to contribute to conventional and quantum computing. While conventional tools (pressure, doping etc.) to modify the band structure are available, time periodic perturbations can provide tunability by adding time as an extra dimension enhanced to the problem. I will review the recent research on topological insulators in non equilibrium situations. Firstly, I introduce briefly the Floquet formalism that allows to describe steady states of the electronic system with an effective time-independent Hamiltonian. Secondly, we summarise recent theoretical work on how light irradiation drives semi-metallic graphene or a trivial semiconducting system into a topological phase. Finally, we show how photons can be used to probe topological edge or surface states.
*Budapest Uni. of Technology and Economics, Budapest, Hungary
The Physics Colloquia are designed to address a non-specialist, broad audience and introduce topics of contemporary research through lectures by leading experts. We warmly invite all members of the student body, including undergraduates enrolled in any programme.