Here you will find some suggested projects. For further information, contact the persons responsible for each project.
Investigating the surface of sea spray aerosol
One of the major uncertainties in our modern climate models originates from the impact of aerosols and sea spray aerosol is one of the most common types of natural aerosol in the atmosphere. It has twofold impact on the earth’s radiation budget. First, by light scattering at the aerosol particles, and second by serving as cloud condensation nuclei. The latter is determined by the composition of the very surface layers of the aerosol particles, which undergoes tremendous changes in dependence on the altitude. At sea level, immediately after their generation from sea water by e.g. breaking waves, sea spray aerosols are liquid droplets. As they rise into higher altitude, the relative humidity decreases and the droplets dry and form a core-shell structure. Depending on the composition of the solution in the initial droplet the surface composition of the dry aerosol can differ and thus impact the efficiency of the particle to act as a cloud condensation nucleus. During this project we will investigate the surface of artificially generated sea spray aerosol with photoelectron spectroscopy at the synchrotron light source SOLEIL in Paris, France. The experiments will take place in the mid-February 2018 and will be part of a collaboration between scientists from Uppsala, Stockholm and Oulu, Finland. Interested students should have a background in physics, chemistry, material science or a related subject.
Design, construction and implementation of a XUV-spectrometer for characterization and optimization of harmonic generation
In this project you will be responsible for the design and construction of a grating based spectrometer in the XUV region. You will evaluate a couple of different design proposals, and based on your evaluation you will purchase the parts needed to construct the spectrometer. With our help you will then implement your solution in our existing experimental setup.
Implementation and initial testing of an experimental chamber for ultra-high vacuum (UHV)
You will be responsible for ensuring that an (already existing) experimental chamber for studies of clean surfaces is fully functional. You will be working mainly with experimental equipment, especially for UHV experiments, where you will learn about the different components, their function and different critical parameters. Once the chamber is operational for UHV experiments you will be conducting the first measurements using our new photon source HELIOS.
Molecular dynamics simulations of protein molecules in laser fields
Simulation study of how the native atomic structure of a protein is affected as it is exposed to an laserfield. Lasers are used as optical tweezers and this study aims to understand how the electric field, the laser field, actually affects the protein structure. The project will involve learning how to use the molecular dynamics program GROMACS.
Atmospheric science of aqueous surfaces
The effects of atmospheric aerosols are identified by IPCC as a key uncertainty in predicting climate change. The surface is important for aerosols due to their small size, but surface effects are not taken into account in current climate models. We study surface composition and speciation on aqueous aerosol model systems of aerosols using synchrotron radiation with the aim of obtaining qualitative and quantitative results to be included in atmospheric modeling.
Validating water models for molecular modeling
In molecular modeling water is often present in one way or another. There are over 50 different water models used by scientists when modeling different phenomena. This project is about comparing the physical and chemical properties of a subset of all the available models to decide which models that good at what. The project will involve learning how to use the molecular dynamics program GROMACS and learning how to evaluate simulations.
RF-filtering and impedance matching for electron lenses used in time-of-flight spectroscopy
We want to convert a scientific apparatus, running adequately with short X-ray pulses with a repetition rate of 1.25 MHz into an instrument that can handle the load from an X-ray source with much higher repetition rate having occasional “lone” pulses at 1.25 MHz. If you want to take part in this development (with first results already achieved) you should be ready to, together with us, develop, build and try out devices that minimizes the RF-interference due to oscillating electric fields inside our instrument.
Shockwaves in materials induced by an X-ray laser
X-ray lasers are new types of lasers, which produce extremely intense and short X-ray pulses. In this project you will use computer simulations to study how shockwaves can be created in a material (eg metal) when it is hit by a focused laser beam and turns into a plasma. This will help us understand how the structure of the material changes and how to control such an extreme process.
Nanoscale Device Physics
Device physics forms the foundation for modern day electronic marvels. Understanding the charge and spin transport, their manipulation in new functional materials is key to the future electronic devices, energy and sensing applications. Nanoscale device Physics is an exciting area of research, where we fabricate nanoscale devices with innovative designs, through state-of-the-art nanofabrication techniques in cleanroom and perform charge/spin transport experiments to uncover the prospect of novel materials and their devices for future applications. The following is a brief outline of the current projects.
Novel graphene spintronic devices
Experimentally realized in 2004, graphene, a one atom thick crystal of carbon atoms placed in a honeycomb lattice, is a material with superlative properties and holds promise for next generation electronics. Spin of electrons, a quantum mechanical property, is responsible for magnetism in solids and forms the basis for an evolving field called ‘Spintronics’. Most successful existing applications of spintronics are the high capacity memory storage devices such as hard disks and MRAM. Research in spintronics is a way for future low power, faster electronic devices. Graphene is prime to spintronics, because it is the best known material for transporting spin information of electrons over long distances. It is anticipated to play a major role in the future of spin based devices in electronics. In this project, our aim is to investigate new spintronic devices of graphene with an aim to enhance their performance with novel device schemes like graphene devices on new substrates that have never been explored before.
Charge and spin transport in new 2D crystals
Two dimensional crystals (2D) are a new class of materials which show special properties for their confined geometry. These crystals are like atomic planes pulled out of bulk crystals having layered structure (stacks of 2D crystals). Graphene, an atomically thin semi-metal is one such crystal that is widely studied and reported in the last decade. In addition, there are semiconducting crystals such as MoS2, WS2, Black Phosphorus which are promising for future transistors, insulating crystals such as h-BN, Fluorographene promising for substrates and tunnel barrier applications, and there are other crystals with exotic properties like topological insulators such as Bi2Se3, Bi2Te3 etc. The number of materials in 2D crystal library is increasing continuously, making the field a lot to be explored. In this project, going beyond the existing crystals, we will investigate the charge and spin transport in new/emerging 2D crystals that show long term promise for applications in nanoelectronic and spintronics.
Magnetic domain wall based devices
A magnetic domain wall separates two domains (regions in space having different directions of magnetic moment) of magnetization in a magnetic material. In the past decade a significant understanding has been developed about the manipulation of domain walls using charge or spin current and their prospect for memory and logic applications. It is now possible to engineer magnetic nanostructures with specific magnetic orientation and domain walls, which can be further manipulated by external magnetic, electrical or optical stimulus. In spite of previous developments, there is plenty of room for new developments that can form the basis for newer technologies. In this project, our aim would be to engineer magnetic nanowires with domain walls, image the domain walls using Magnetic force microscopy and manipulate them using charge and pure spin currents. The nanowires will be fabricated using the state of the art e-beam lithography technique at the Ångström Microstructure Laboratory, which will be followed by the said experiments. In the next step such magnetic structures will be integrated with non-magnetic spin current carriers such as aluminum or graphene nanowires in pursuit of novel spintronic devices.
Molecular dynamics of organic molecules on water surfaces
The behavior of small organic molecules on water surfaces is important for atmospheric chemistry. Molecules that show surface preference have a larger possibility to interact with the surrounding atmosphere. We have studied how small organic molecules such as carboxylic acids and alcohols behave in a water/gas interphase both experimentally and using molecular dynamics. This project is focused on doing a simulation study of how the structure of different organic molecules affect the molecules surface preference. Simulations will be done using the molecular dynamics package GROMACS and will be strongly connected to experimental results that from studies at synchrotron source such as MAXlab.
Experimental Study and Simulation of Liquid Interfaces
The properties of liquid surfaces and interface differ fundamentally from the bulk. It is therefore crucial to understand the behaviour of solutions in proximity to such an interface. Two powerful tools to study these systems are photoelectron spectroscopy and molecular dynamics (MD) simulations. In this project you would study aqueous solutions containing various solutes (e.g. small molecules and ions) using our in-house experiment a well as synchrotron light source setups. Our setup combines a liquid jet with a hemispherical photoelectron analyzer, which allows us to selectively observe the interface of the liquid and can also be modified to study aerosols. The experimental results would then be supported by MD simulations which are crucial if one wants to understand the mechanisms behind the observed experimental effect.