ICPS 2014

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8:30-8:45
Oral: Stephan Baer
Measurements of Quasi-Particle Tunneling in the Second Landau Level
Co-authors: Clemens Rössler, Thomas Ihn, Klaus Ensslin, Christian Reichl, Werner Wegscheider

8:45-9:00
Oral: Lina Bockhorn
Negative Magnetoresistance Induced by Rare Strong Scatterers
Co-authors: Igor V. Gornyi, Dieter Schuh, Christian Reichl, Werner Wegscheider, Rolf J. Haug

9:00-9:30
Oral: Milan Orlita
Massless Fermions in 2D & 3D: Infrared Magneto-Spectroscopy Studies
Co-authors: N/A 

Solid-state physics and quantum electrodynamics, with its relativistic (massless) particles, meet in steadily expanding class of materials. Those include, 1D carbon nanotubes, 2D graphene or topological-insulator surfaces, and most recently, the systems with 3D conical dispersion - with Weyl, Dirac or Kane fermions. In this talk, I will review how the linear dispersion impacts the (magneto-) optical properties of these systems.

We focus on two representative materials: a 2D graphene and bulk HgCdTe which displays the 3D conical dispersion when tuned to the point of the semiconductor-to-semimetal transition. We show that it is the number of dimensions, which defines the (joint) density of states, and in consequence, the simple physical quantities such as absorption of light - dispersionless in graphene but displaying a linear-in-photon-energy dependence in HgCdTe. In magnetic field, the optical response is determined by by electronic excitations between discrete or dispersion Landau levels (in 2D or 3D), both, however, with a typical for relativistic particles, square root dependence on the magnetic-field. Further relativistic effects may appear, depending on the strength of spin-orbit coupling. Spin-related effects are rather absent in the optical response of graphene which exhibits a weak spin-orbit coupling. Instead, we observe a pronounced spin splitting of levels in HgCdTe, which follows the square-root-magnetic-field dependence - a well-established signature of relativistic particles.

9:30-9:45
Oral: Masayuki Hashisaka
Fractional Charge Tunneling through a Local Fractional Quantum Hall Region
Co-authors: Tomoaki Ota, Koji Muraki, Toshimasa Fujisawa

9:45-10:00
Oral: Ramesh Mani
Size Dependent Giant Magnetoresistance in Millimeter-Sized GaAs/AlGaAs Devices
Co-authors: Annika Kriisa, Werner Wegscheider

10:00-10:15
Oral: Stephan Smolka
Cavity Quantum Electrodynamics as a Sensitive Probe of Many-Body Physics in Two Dimensional Electron Gases 
Co-authors: Wolf Wüster, Florian Haupt, Stefan Faelt, Werner Wegscheider, Atac Imamoglu 

10:15-10:30
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