Studentprojekt

Här finner du några föreslagna projekt. För vidare information, vänligen kontakta personerna ansvariga för respektive projekt. Kolla gärna den engelska sidan för flera projekt med beskrivning på engelska.


Design samt konstruktion och implementation av en XUV spektrometer för karakterisering och optimering av övertonsgeneration

Abstract
I detta projekt kommer du att ansvara för design samt konstruktion av en gitterbaserad spektrometer i XUV området. Du kommer att utvärdera ett par olika design-förslag, baserat på din utvärdering kommer du att köpa in delar som krävs för att konstruera spektrometern. Med hjälp av oss kommer du sedan att implementera din lösning i vår existerande experimentuppställning.

Kontakt
Johan Söderström


Implementation samt första tester av en experimentkammare för ultrahögt vakuum (UHV)

Abstract
Du kommer att ansvara för att en (redan existerande) experimentkammare för studier av rena ytor är fullt fungerande. Du kommer att arbeta mycket med experimentell utrustning, speciellt för UHV experiment, där du kommer att lära dig om de ingående komponenterna, dess funktion och olika kritiska parametrar. När kammaren väl fungerar för UHV experiment så kommer du att göra de första mätningarna med den vid vår nya fotonkälla HELIOS.

Kontakt
Johan Söderström
Anders Sandell


Molekyldynamiksimuleringar av proteinmolekyler i laserfält

Abstract
En simuleringsstudie över hur den nativa atomstrukturen hos ett protein påverkas är den utsätts för ett laserfält. Lasrar används som optiska pincetter ("optical tweezers") och den här studien ämnar att förstå hur det elektriska fältet, laserfältet, faktiskt påverkar proteinstrukturen. Det här projektet kommer också att innefatta att lära sig hantera molekyldynamikprogrammet GROMACS.

Kontakt
Carl Caleman


Atmosfärvetenskap hos vattenhaltiga ytor

Abstract
Effekterna av atmosfäriska aerosoler anses av IPCC vara en nyckelkomponent till den föreliggande osäkerheten i klimatförändringsprognoser. Ytan är viktig för aerosoler på grund av deras minimala storlek, men yteffekter has inte hänsyn till alls i nuvarande klimatmodeller. Vi studerar ytsammansättning och differentiering av vattenhaltiga aerosol-modellsystem hos aerosoler med synkrotronstrålning, och målet är att erhålla kvalitativa och kvantitativa resultat som kan användas i atmosfärisk modellering.

Kontakt
Olle Björneholm


Validerande av vattenmodeller för molekylär modellering

Abstract
I molekylär modellering är vatten är ofta närvarande på ett eller annat sätt. Det existerar över 50 olika vattenmodeller som forskare använder när de modellerar olika fenomen. Det här projektet handlar om att jämföra de fysikaliska och kemiska egenskaperna hos en delmängd av alla tillgängliga modeller för att avgöra vilken modell som är bra för vad. Projektet kommer att innefatta att lära sig hantera molekyldynamikprogrammet GROMACS samt att lära sig utvärdera simuleringar.

Kontakt
Carl Caleman


RF-filtrering och impedansmatchning för elektronlinser använda vid flygtidsspektroskopi

Abstract
Vi vill omvandla ett vetenskapligt instrument som fungerar bra med korta röntgenpulser med en repetitionshastighet på 1.25 MHz till ett instrument som kan hantera belastningen från en röntgenkälla med avsevärt högre repetitionshastighet och med enstaka pulser på 1.25 MHz. Om du vill vara delaktig i den här utvecklingen (där de första resultaten redan har erhållits) ska du vara redo att, tillsammans med oss, utveckla, bygga och testa anordningar som minimerar RF-störningar orsakade av oscillerande elektriska fält i vårt instrument.

Kontakt
Andreas Lindblad


Stötvågor i material inducerad av röntgenlaser

Abstract
Röntgenlasrar är en ny typ av lasrar som producerar extremt korta och starka röntgenpulser. I detta projekt kommer att du att använda datorsimuleringar för att studera hur stötvågor kan skapas i ett material (t.ex. metall) när det träffas av en fokuserad laserstråle och förvandlas till plasma. Detta kommer att hjälpa oss förstå hur materialstrukturen påverkas och hur en sådan extrem process kan kontrolleras.

Kontakt
Nicusor Timneanu


Atomära modeller för energetiska material

Abstract
Molekyldynamik (MD) har utvecklats till en väletablerad beräkningsmetod som med adekvata kraftfält har visat sig kunna förutsäga viktiga egenskaper för en rad olika materialtyper. Inom forskning relaterad till rymd- och försvarsforskning finns ett behov av att optimera olika materialegenskaper; sprängämnen och krut med låg stöt och temperaturkänslighet, förbättrade bränslen för rymdfarkoster eller polymerer skräddarsydda för diverse tillämpningar. I detta arbete kommer någon av MD-programmen GROMACS eller LAMMPS att användas för att utvärdera lämpligt kraftfält i syfte att förutsäga ett antal grundläggande fysikaliska egenskaper för några utvalda material. Arbetet utförs i samarbete med FOI, Totalförsvarets forskningsinstitut.

Kontakt
Carl Caleman


Experimentell studie och simulering av vätskeytor

Abstract
Egenskaperna hos vätskeytor och gränssnitt skiljer sig fundamentalt från de hos bulken. Det är därför viktigt att förstå beteendet hos lösningar i närheten av ett sådant gränssnitt. Två kraftfulla verktyg för att studera dessa system är fotoelektronspektroskopi och simuleringar med hjälp av molekyldynamik (MD). I detta projekt skulle du studera vattenlösningar innehållande olika lösta ämnen (t ex små molekyler och joner) med hjälp av vår egna experimentuppställningar såväl som med synkrotronkällor. Vår uppställning kombinerar en vätskestråle med en halvsfärisk fotoelektronanalysator, som tillåter oss att selektivt observera vätskans gränsyta och kan också modifieras för att studera aerosoler. De experimentella resultaten skulle stödjas av MD-simuleringar, vilket är avgörande om man vill förstå mekanismerna bakom den observerade experimentella effekten.

Kontakt
Clara Saak
Olle Björneholm
Carl Caleman


Nanoscale Device Physics

Overall theme
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.

Contact
Venkata Kamalakar


Atmospheric Chemistry

Atmospheric Chemistry

We are interested in revealing molecular scale processes influencing the climate. The main subject of our investigations in this field are aerosols. These are particles with a wide range of diameters immersed in gas. Aerosols are released into the atmosphere in large amounts from e.g. vegetation, dust, combustion engines or sea spray. Thus, aerosols play an important role in atmospheric science since they impact the climate in various ways. On one hand they scatter sunlight as well as infrared radiation from the earth’s surface, they act as seeds for cloud condensation and they facilitate chemical reactions at their surface. All these aspects happen on a big scale in the atmosphere and are complex. Many methods nowadays used in atmospheric science do not deliver molecular-level information and thus our knowledge about processes in aerosol particles on the microscopic level is still limited. We utilize photoelectron spectroscopy to aerosol particles to obtain molecular level information about selected aspects of aerosols and thus contribute to an overall understanding of their impact on the climate.

Our experiments are usually conducted at the synchrotron light sources SOLEIL (Paris, France), BESSY II (Berlin, Germany), SIRIUS (Campinas, Brazil) and MAX IV (Lund, Sweden). The teams working on these projects consist of researchers with various skills and cultural backgrounds to cover as many aspects as possible of such a broad subject. Therefore, interested students should be open to acquire knowledge from various scientific fields during the project work and ideally have a background in chemistry, physics or a related field.

Contact
Olle Björneholm
Geethanjali Gopakumar
Clara Saak
Isaak Unger


Fundamental Processes in Liquids

Our research addresses questions that are at the very basis of e.g. atmospheric chemistry, biophysics and our renewable energy related projects. This work focusses on intermolecular interactions in liquids (e.g. hydrogen bonds in water) and how they react to changes of the system like the solution of salts or varying temperatures. We aim to understand how such changes take effect on the molecular level and the tool for our investigation is photoelectron spectroscopy. This technique allows us to obtain spacial and temporal information about our samples. Thus we can investigate the surface propensity of solutes in a liquid or investigate dynamics on a femtosecond timescale. Since we strive for a holistic understanding, we also combine our experiments with investigations on clusters or molecules in the gas phase.

Our experiments usually take place at the synchrotron light sources SOLEIL, Paris (France), BESSY, Berlin (Germany), MAX IV, Lund (Sweden) or LNLS / SIRIUS, Campinas (Brazil). During the experiments we work closely together with scientists from other institutions with diverse scientific backgrounds.

Interested students ideally have a background in chemistry, physics or a related subject and should be open to acquire knowledge from other scientific fields since our projects often use methods from physics applied to questions motivated from chemistry.

Contact
Olle Björneholm
Geethanjali Gopakumar
Clara Saak
Isaak Unger


Biophysics and Biochemistry

Biophysics and biochemistry

Our group addresses how biological processes work on the molecular scale and we employ photoelectron spectroscopy to obtain the desired, molecular-level information. Currently, we are working on two main topics:

  1. Radiation-induced damage to biologically relevant molecules
  2. The surface propensity of organic molecules in aqueous solutions

Radiation-induced damage
Whenever we travel in high altitude (e.g. flying in a plane) or receive an X-ray of the skeleton, we are subjected to radiation induced damage. If high-energy photons interact with matter they can trigger a multitude of reactions we currently lack detailed knowledge of. Consider two cases: A photon hits a biomolecule directly and ionizes it. The molecule may either dissociate directly or undergoes further relaxation and then breaks apart. Which of the two cases takes place? That is determined by which molecular level has been initially ionized and the structure of the molecule. However, we are currently not able to predict precisely which parameters favour one over the other process and that’s what our research focusses on.

Surface propensity of molecules
The biological relevance of the second aspect of our research, the surface propensity of biomolecules, becomes apparent when considering all the interfaces between aqueous solutions and e.g. protein surfaces or cell membranes in the body. We try to learn under which conditions ions and molecules are either repelled to drawn to these interfaces and what the driving forces for these dynamics are. By understanding these, we contribute to resolving questions about e.g. protein folding and the transfer of molecules through membranes. This aspect of our research is closely related to the fundamental properties of solutions, which is another one of our research topics.

We use synchrotron light sources in Europe and abroad for our experiments. The most commonly used synchrotron facilities by our group are SOLEIL (Paris, France), BESSY II (Berlin, Germany), MAX IV (Lund, Sweden) and SIRIUS (Campinas, Brazil). The research projects are carried out in collaboration with other researchers from all around the globe and with very different scientific backgrounds. Therefore, interested students should be open to acquire knowledge from other scientific fields but their own as part of the project work and should have a background in biology, chemistry, physics or a related field.

Contact
Olle Björneholm
Geethanjali Gopakumar
Clara Saak
Isaak Unger


Catalysis and Renewable Energy

The earth receives more energy from the sun through radiation than we need - even in our energy-hungry technological society. Methods for harvesting this energy are in development but the efficient storage of the harvested energy is a major challenge. One obvious approach is to transform electrical energy into chemical energy e.g. by splitting water or carbon dioxide. In order to use these electrochemical reactions efficiently and on a large scale, we need cheap catalysts with high turnover rates and a long lifetime.

Catalysis

In order to develop the next generation of efficient and durable catalysts, our research group collaborates with other researchers from Uppsala University and the University of Sao Paulo (Brazil). We strive to obtain a molecular level understanding of the function of the catalysts and all the individual steps of the catalytic process. In order to achieve this we employ photoelectron spectroscopy to investigate catalysts. The sample environment during the investigation ranges from solid state samples, gaseous samples to complexes dissolved in water.

Our experiments are conducted at synchrotron the light sources SOLEIL (Paris, France), BESSY II (Berlin, Germany), MAX IV (Lund, Sweden) and SIRIUS (Campinas, Brazil). The experimental teams are composed of researchers with varying professional and cultural background.

Interested students ideally have a background in chemistry, physics or a related field and should be open to acquire knowledge from other scientific areas since our projects reach across the borders of traditional scientific subjects.

Contact
Olle Björneholm
Isaak Unger