Catalysis and surface oxidation
This project involves studies of atomic processes in model systems in order to obtain a fundamental understanding of the material, its electronic structure and important surface processes. Studies of catalytic processes on model surfaces involve systems such as metals, oxides, metallic clusters and nanostructures on surfaces. We are involved in several networks on catalysis research which are funded by VR, SSF and NordForsk.
We develop and use methods for analysis of nanostructures with highest possible spatial and temporal resolution. One aim of this research is to understand the role of the surfaces and interfaces for their function and properties. Another goal is to study devices under as realistic conditions as possible. The aim is both fundamental physical understanding as well as enabling the design of novel devices. We study primarily semiconductors for light-emitting diodes, solar cells, low-energy electronics, and computation.
To this end, we use a wide range of X-ray methods at different synchrotrons, including MAX IV in Lund as well as ESRF and PETRA-III, ultrafast lasers at Lund Laser Centre, and a variety of high resolution scanning probe microscopes maintained by our division, including Sweden’s largest facility for scanning tunneling microscopy. We collaborate with many other researchers in particular within NanoLund, elsewhere at Lund University, and internationally.
Electron spectroscopy has provided much of our current knowledge on the chemical and physical processes involved in the complex interactions between a solid surface and its surroundings. Such processes are for example important for surface catalysis, corrosion and thin film growth.
As the surface state depends strongly on its environment, it is vital that such studies are performed under realistic in situ and/or operando conditions. Recently, ambient pressure x-ray photoelectron spectroscopy (APXPS) has been introduced as a powerful method to approach such questions due to the sensitivity to the chemical state of the substrate as well as of the adsorbates. Whereas it is not possible to perform electron spectroscopy at realistic pressures for e.g. industrial catalytic reactions, the attainable pressures in the range of 0.01 to of ca. 30 mbar are in most cases sufficient for modelling real reaction conditions.
The HIPPIE and SPECIES beamlines at the MAX IV Laboratory are key infrastructure for this project, and our main research focuses are catalysis, thin film growth (atomic layer deposition, ALD, and chemical vapour deposition, CVD) and chemistry below graphene.
Atomic, molecular and cluster dynamics
We are interested in understanding the photoionization of atoms, molecules, and clusters. The group is involved in experiments using synchrotron radiation where core electron excitation is an important start for dynamic processes resulting in fragmentation. We have a long history in electron spectroscopy of atoms, molecules and clusters and now imaging experiments where electrons or ions are detected have been developed within the group.
Most of the soft x-ray experiments were carried out at MAX-Lab and nowadays at MAXIV laboratory. Time-resolved studies are carried out in collaboration with scientists at the Lund Attosecond Science Center using the attosecond light sources from Lund Laser Center.
The interactions of electrons in materials are a rich and complex source of physical problems, in part due to the issues brought about by dealing with the large number of electronic many-body interactions, both with other electrons and with the parent ions. These interactions give rise to fundamentally quantum mechanical states such as superconductivity and magnetism. New quantum states of matter are being uncovered on a regular basis.
We focus on using scattering techniques to look at the structure and dynamics associated with these strong electron corrrelations, particularly neutron and X-ray methods. To this end, we use a wide range of neutron facilities and synchrotron radiation facilities in Europe and around the world, soon to include the European Spallation Source at Lund. We also work on sample growth and characterizations using our lab facilities here.