Scientific Highlights
The competition between organics and bromide at the aqueous solution – air interface as seen from ozone uptake kinetics and X-ray photoelectron spectroscopy
A more detailed understanding of the heterogeneous chemistry of halogenated species in the marine boundary layer is required. Here, we studied the reaction of ozone (O3) with NaBr solutions in presence and absence of citric acid (C6H8O7) under ambient conditions. Citric acid is used as a proxy for oxidized organic material present at the ocean surface or in sea spray aerosol.
Local current measurement in PEFC
Major barriers for a successful commercialization of Polymer Electrolyte Fuel Cells (PEFCs) are insufficient lifetime and high cost of platinum catalyst. A comprehensive understanding of aging and transport phenomena on all relevant length scales is a key to improve durability and to reduce precious metal loading. Flow fields as used in PEFCs for the distribution of the reactant gases over the electrode area cause inhomogeneities. The importance of down the channel inhomogeneities has been realized.
Observation of a d-wave nodal liquid in highly underdoped Bi2Sr2CaCu2O8+δ
A key question in condensed-matter physics is to understand how high-temperature superconductivity emerges on adding mobile charged carriers to an antiferromagnetic Mott insulator. We address this question using angle-resolved photoemission spectroscopy to probe the electronic excitations of the non-superconducting state that exists between the Mott insulator and the d-wave superconductor in Bi2Sr2CaCu2O8+δ.
How fast can the lattice symmetry of a solid change?
One approach to advance our understanding of the complex interactions between different degrees of freedom in strongly correlated systems is to use time-resolved methods to study the response of a material after it has been driven out of equilibrium. Ultrafast optical techniques have demonstrated considerable potential to unravel the correlations that drive the interesting physics in such materials.
Watching atoms move: an ultrafast phase transition
One approach to advance our understanding of the complex interactions between different degrees of freedom in strongly correlated systems is to use time-resolved methods to study the response of a material after it has been driven out of equilibrium. Ultrafast optical techniques have demonstrated considerable potential to unravel the correlations that drive the interesting physics in such materials.
Watching atoms move
A complete characterization of the unit cell dynamics of a laser-excited tellurium crystal is demonstrated using femtosecond x-ray diffraction. The analysis offers a quantitative measure of the unit cell dynamics without making any assumptions on the symmetry of the excited-state motion.
Confinement-Induced Orientational Alignment of Quasi-2D Fluids
Extreme confinement is known to induce ordering of the fluid, thereby affecting its properties.
Advanced phase contrast imaging using a grating interferometer
Conventional absorption based X-ray microtomography can become limited for objects showing only very weak attenuation contrast at high energies. However, a wide range of samples studied in biology and materials science can produce significant phase shifts of the X-ray beam and thus phase contrast X-ray imaging can provide substantially increased contrast sensitivity.
Electrons with opposite spins move in opposite directions
In one dimension, there are only two ways to move: left or right. This leads to some peculiar properties for one-dimensional systems on the atomic scale.
Phonon squeezing
Photon squeezing has been the subject of intense interest in the field of quantum optics, since it serves as a unique demonstration of the quantum nature of light. On a practical level, squeezing offers opportunities to make interferometric measurements much more precise than would normally be allowed by quantum uncertainty limits.