Nanomaterials & Scattering (O. Paris)
Research of the Nanomaterials & Scattering working group is focused on the physics of nanostructured materials. Current activities are experiments and simulation of structure-property relationships in complex materials and like nanostructured carbons and ceramics, inorganic nanoparticles, micro and mesoporous materials, and hierarchical biological and biomimetic structures. We use particularly in-situ scattering techniques to study nanoscale structure and processes in complex systems such electrosorption in supercapacitor electrodes or gas adsorption in nanoporous materials. Recent projects include the following subjects:
- Adsorption and phase-behavior of fluids in confined geometry of nanoporous materials and their sorption induced deformation
- Electrosorption of ions in model supercapacitor electrodes based on microporous carbons, including local ion arrangement and dynamics, as well as electrosorption-induced deformation
- Hierarchical plant tissues used as a framework to create casting molds for novel nanostructured inorganic materials (Biotemplating)
- Structure-function relations of biomineralized- and cellulosic tissues
- Structural and crystalline properties of colloidal nanoparticles
- Nanostructured and nanomechanical properties of carbon nanomaterials
We particularly focus on the advancement of new in-situ scattering techniques using conventional X-ray sources as well as synchrotron radiation and neutron sources, and we develop new data analysis concepts and and data simulation tools. With these advanced techniques we are able to observe changes occurring on the nanometer scale in “real time”, i.e. we are “watching materials at work”.
Surface Physics & Scanning Probe Microscopy (C. Teichert)
The Scanning Probe Microscopy group at the Institute of Physics of the Montanuniversität in Leoben is concerned with the exploration of surface nanostructures and its physical properties by means of atomic force microscopy (AFM) and related techniques. Of major interest are self-organized organic semiconductor nanostructures formed during heteroepitaxial and ion-bombardment processes as well as the revelation of molecular processes in the growth of organic semiconductor thin films. A current FWF (Austrian Science Fund) project is dedicated to the investigation of the growth of polar organic molecules on two-dimensional materials like graphene or hexagonal boron nitride. Methods like conductive atomic force microscopy (C-AFM) and Kelvin probe force microscopy (KPFM) are utilized to investigate electrical properties of dielectric and piezoelectric materials on the nanometer scale.
In the framework of a CD (Christian Doppler) Laboratory the viscoelastic properties of cellulose fibers as a function of humidity are determined. Finally, also quantitative roughness analyses and contact angle measurements on the complete spectrum of materials ranging from steel to polymers are executed.
Simulation of Electric Transport (J. Oswald)
We study many-body interaction effects in the spatially resolved filling factor ( ν) distribution for higher Landau levels (LLs) via self-consistent Hartree-Fock simulations in the integer quantum Hall (IQH) regime. Our results indicate a strong, interaction-induced tendency to avoid the simultaneous existence of partially filled spin-up and spin-down LLs. Rather, we find that such partially filled LLs consist of coexisting regions of full and empty LLs. At the boundaries between the regions of full and empty LLs, we observe edge stripes of nearly constant ν close to half-filling. This suggests that the exchange interaction induces a behavior similar to a Hund's rule for the occupation of the spin split LLs. The screening of the disorder and edge potential appears significantly reduced as compared to static Thomas-Fermi screening (C hklovskii D. B. et al., Phys. Rev. B, 46 (1992) 4026). Our results are consistent with a local, lateral ν-dependence of the exchange-enhanced spin splitting. Hence, on quantum-coherent length scales as probed here, the electron system of the IQH effect behaves similarly to a non-interacting single particle system —not because of the absence, but rather due to the dominance of many-body effects.
for more details see: http://iopscience.iop.org/article/10.1209/0295-5075/117/57009
Photonics & Nanoelectronics (R. Meisels)
We deal with numeric and experimental simulations of the propagation of electromagnetic waves, in particular with the design of photonic structures, and with the spectroscopy in the ranges from microwaves (GHz) into the EUV (extreme ultraviolet) (nm).
Applications range from the simulation of the electric field in quantum detectors, the propagation of microwaves in rocks to facilitate mining, to the study of multi layer mirrors for the EUV (13.5 nm).