669 research outputs found
Probing Quantum Confinement and Electronic Structure at Polar Oxide Interfaces
Polar discontinuities occurring at interfaces between two different materials
constitute both a challenge and an opportunity in the study and application of
a variety of devices. In order to cure the large electric field occurring in
such structures, a reconfiguration of the charge landscape sets in at the
interface via chemical modifications, adsorbates or charge transfer. In the
latter case, one may expect a local electronic doping of one material: one
sparkling example is the two-dimensional electron liquid (2DEL) appearing in
SrTiO once covered by a polar LaAlO layer. Here we show that tuning the
formal polarisation of a (La,Al)(Sr,Ti)O (LASTO:) overlayer
through chemical composition modifies the quantum confinement of the 2DEL in
SrTiO and its electronic band structure. The analysis of the behaviour in
magnetic field of superconducting field-effect devices reveals, in agreement
with calculations and self-consistent Poisson-Schr\"odinger
modelling, that quantum confinement and energy splitting between electronic
bands of different symmetries strongly depend on interface charge densities.
These results not only strongly support the polar discontinuity mechanisms with
a full charge transfer to explain the origin of the 2DEL at the celebrated
LaAlO/SrTiO interface, but also demonstrate an effective tool for
tailoring the electronic structure at oxide interfaces.Comment: 18 pages, 4 figures, 1 ancillary file (Supporting Information
Eye tracking as a modality:état des lieux de l’interaction eye-based en vue d’une intégration aux interactions proxémiques
Summer Academy:for social media trainers in local regional governments and business
One of the work packages which Hanzehogeschool emphatically has a role, is Research and Training. In the Summer Academy teachers are trained by translating their knowledge back to their own schools. The Summer Academy is given on 27-30 May 2013, as part of "Opening Up". This project aims to find better service to citizens and businesses through the use of social media and open data. The opening-up project started in October 2011 and lasts three years. Hanze University Groningen is an important partner in the project
Nanoparticles and Taylor dispersion as a linear time-invariant system
The physical principles underpinning Taylor dispersion offer a high dynamic range to characterize the hydrodynamic radius of particles. While Taylor dispersion grants the ability to measure radius within nearly 5 orders of magnitude, the detection of particles is never instantaneous. It requires a finite sample volume, a finite detector area, and a finite detection time for measuring absorbance. First we show that these practical requirements bias the analysis when the self-diffusion coefficient of particles is high, which is typically the case of small nanoparticles. Second we show that the accuracy of the technique may be recovered by treating Taylor dispersion as a linear time- invariant system, which we prove by analyzing the Taylor dispersion spectra of two iron-oxide nanoparticles measured under identical experimental conditions. The consequence is that such treatment may be necessary whenever Taylor dispersion analysis is not optimized for a given size but dedicated to characterize broad groups of particles of varying size and material
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