# Education

To study materials theory we recommend that you during Bachelor studies take courses focusing on quantum physics, statistical mechanics, and condensed matter theory.

At the Master’s level we offer several programs with excellent opportunities to study materials theory:

More specifically, we offer courses within Density functional theory (DFT), Electronic structure calculations, Many body theory, Solid state theory, Magnetism, Physics of energy related materials, Quantum materials, Quantum information and Next generation quantum technology. There also exists several opportunities to try out research within materials theory through different project courses. We additionally offer a large selection of projects for Bachelor and Master theses, see links.

For PhD studies, all positions are advertised on the departments website and the university job portal. Current research topics within the division are described under Materials Theory and Quantum Matter Theory.

## Bachelor Thesis Projects at Materials Theory

Below you can see a list of bachelor thesis projects that the division of Materials Theory is posting at the moment. For more information, please contact Olle Eriksson or Susanne Mirbt.

See also the list of master thesis proposals as some of these may be suitable as bachelor projects as well.

### First principles electronic structure calculations

The students will learn to perform state-of-the-art first principles electronic structure calculations using several softwares to calculate the properties of realistic materials. The specific projects are the following.

- Calculation of force constant matrices of disordered alloys
- Optical properties of metals and semiconductors
- Electron correlations in complex oxides
- Extraction of tight binding parameters for graphene and related materials

**Contact**

Dr. Biplab Sanyal

Room: Å13241

### Simulating the electron microscope

The project aims to simulate the scattering of electrons in a crystal. Elastic and inelastic scattering processes in an electron microscope reveal a wealth of information about samples – composition, electronic and magnetic properties. It is the latter ones that will be in our focus.

**Contact**

Dr. Jan Rusz

### New permanent magnet materials

Using calculations of the electronic structure, we will evaluate magnetic properties of selected crystals. We will focus on magnetic properties that are essential for good permanent magnet materials. For this project there is a space for more people, that could work in a team, studying different classes of materials.

**Contact**

Dr. Jan Rusz

### Dynamics of quantum spin under non-equilibrium

The student will learn and use quantum field theoretical methods that are suitable for this type of dynamics studies. Moreover, numerical implementation and computations of the spin dynamics will be of great importance. The student can choose between making theoretical and/or numerical studies.

**Contact**

Dr. Jonas Fransson

## Master Thesis Projects at Materials Theory

Below you can see a list of master thesis projects that the division of Materials Theory is posting at the moment. For more information, please contact Olle Eriksson.

See also the list of bachelor thesis proposals as some of these may be suitable as master projects as well.

### Calculations of terahertz conductivity of twisted bilayer graphene

Twisted bilayer graphene (TBG) is formed when two graphene monolayers are stacked on top of each other with a relative twist. The electronic properties of twisted bilayer graphene are drastically different compared to monolayer or bilayer graphene. Light is a fantastic probe for understanding the modification in the electronic properties of TBG. Recently, the terahertz conductivity of the twisted bilayer graphene was measured. Another recent work proposed to find the twist angle of TBG with high harmonic generation by analyzing the polarization properties of the emitted harmonics.

The aim of the project is to understand TBG using the linear response theory to compute the THz conductivity. In addition, the conductivity as a function of the light polarization can be analyzed to see whether we see an effect similar to the recent proposal within the perturbative limit.

**Contacts**

M.S. Mrudul

Peter Oppeneer

### Chiral molecules as spin selective current filters

Spin selective processes are of major importance in molecular electronics, especially as the basis for next-generation low-energy spintronic devices. In recent years, chiral molecules such as DNA, attached to electronic leads, have been intensely studied due to their demonstrated ability to carry spin-selective current when driven intoned-equilibrium. The magnitude of this effect however continues to elude theoretical explanation, as it is orders of magnitude larger than expected from simple theory.

This project concerns the theoretical modelling of this phenomenon using a newly developed model that takes electron interactions into account for the first time. In this project, the aim is to explore to what degree these interactions can explain the current gap between experiment and theory, with the aim of ultimately paving the way for realistic modelling of these spintronic devices. The emphasis for this work is integrating numerical and analytical approaches to describe the systems of interest.

**Contacts**

Jonas Fransson

Jonas.Fransson@physics.uu.se

### Applications of ab initio molecular dynamics in cemented carbides sintering (Sandvik Coromant)

During sintering of cemented carbides, the evolution of the microstructure can be controlled by changing the chemical potentials in the raw material powders, or in the atmosphere. The transport of elements trough the liquid binder phase however differs between elements. In this project we will calculate, using ab initio molecular dynamics simulations, the mobility of different elements in the liquid binder. It is furthermore the aim to investigate how interactions between elements affect the diffusion rates.

**Contact**

Andreas Blomqvist

andreas.blomqvist@sandvik.com

+46 (0)8 726 64 24

### Properties of the d+id-wave superconducting graphene

This project involves theoretical and numerical modeling of the proposed d+id-wave superconducting state in graphene. Interesting aspects that can be investigated are impurities, domain walls, and vortices.

**Contact**

Annica Black-Schaffer

### Spin-orbit coupled impurities in topological insulators

This project involves theoretical and numerical modeling of spin-orbit coupled impurities on the surface of a topological insulator. Special attention will be paid to the magnetic properties of the impurity-induced resonance peaks.

**Contact**

Annica Black-Schaffer

### Impurities in spin-orbit coupled semiconductors with proximity-induced superconductivity

Depositing a superconductor on top of a spin-orbit coupled semiconductor can produce a topological superconductor, which hosts Majorana fermions in vortex cores. This project involves theoretical and numerical modeling of the effects of impurities in these systems.

**Contact**

Annica Black-Schaffer

### First principles theory of complex oxides

**Supervisor**

Biplab Sanyal

### Exploring physics of graphene by realistic simulations

**Supervisor**

Biplab Sanyal

### Vibrational properties of random alloys from first principles theory

**Supervisor**

Biplab Sanyal

### Structure and magnetism of nanoclusters

**Supervisor**

Biplab Sanyal

### Non-equilibrium dynamics of localized spin on metallic surface

**Supervisor**

Jonas Fransson

### Effects of local vibrations on the electronic structure of graphene

**Supervisor**

Jonas Fransson

### Inelastic scattering effects of magnetic impurities on topological insulators

**Supervisor**

Jonas Fransson

### Dynamics of a magnetic moment in a Josephson junction

**Supervisor**

Jonas Fransson

### Theoretical studies of molecular spin pump systems

**Supervisor**

Jonas Fransson

### Theory of ultrafast laser-induced demagnetization

**Supervisor**

Peter Oppeneer

### Computational theory of spin thermal transport

**Supervisor**

Peter Oppeneer

### Theory and calculations for novel x-ray magnetic spectroscopy

**Supervisor**

Peter Oppeneer

### Laser-induced ultrafast spin currents

Our group has recently developed a novel microscopic theory to explain how an ultrashort laser pulse could modify the magnetic system within a few hundred femtoseconds after laser excitation. The purpose of this project is to improve the electron transport description within this model by introducing a new source of electron scattering, which hitherto has been missing, the electron-phonon scattering. Another aim of this project is to develop theory of spin current-induced torques in magnetic materias.

**Contact**

Pablo Maldonado and Peter Oppeneer

### Realistic modelling of superconducting materials

We have recently developed a state-of-the-art computational framework for the realistic modelling of superconductors by combining quantum field theoretical methods with DFT ab initio calculations. Several projects where students can get familiar with this powerful technique are available. These include employing the already developed tools to study superconductors of current interest and/or incorporating and testing new features to the present codes like for example impurity scattering effects.

**Contact**

Alex Aperis and Peter Oppeneer

### Hidden order and superconductivity in URu2Si2

Below 17.5 K, URu2Si2 exhibits a phase transition into a yet unidentified quantum state, the so-called “hidden order” (HO). The nature of the HO has remained a highly controversial and hot topic in the field of strongly correlated electrons for the last 30 years, despite the immense scientific activity on the subject. Interestingly, while in the HO phase and below 1.5 K, URu2Si2 becomes an exotic superconductor. The goal of this project is to study numerically the interplay between superconductivity and different candidate states for the HO. This should bring us a step closer in solving the puzzle of the HO in this material.

**Contact**

Alex Aperis and Peter Oppeneer

### Theory of Quasi-Particle Interference (QPI) in multicomponent systems

During the last decade, Quasi-Particle-Interference has emerged as a key experimental technique for the momentum-resolved imaging of quasiparticles in the superconducting state. The goal of this project is to develop a numerically efficient, generalized framework for the simulation of QPI experiments in materials where multiple quantum states of matter (e.g. superconductivity, antiferromagnetism, etc.) coexist.

**Contact**

Alex Aperis and Peter Oppeneer

### Polymer physics with focus on proteins

**Overall goal**

Proteins can without any exaggeration be called the “building bricks of life”. The proper work of all alive organisms depends on a proper work of the proteins they consist of. And the proper work of proteins depends not only on their chemical structure, but on their three dimensional shape.

While much effort so far has been concentrated on investigating specific proteins to understand their particular properties, it is also of interest to study more general models to discover universal behaviour.

For that reason we are working on an effective Hamiltonian which can describe thermodynamical properties of polymer chains, which should be considered as a first approach to model all polypeptides. This Hamiltonian can reproduce both secondary and tertiary structures of proteins. To investigate the properties of this system we perform classical Monte Carlo simulations, using our own software.

Since the topic is new there are many things that can be done there. Thus all projects are quite flexible and can be adjusted according your interests, skills and preferences. However, basic programming skills are required.

**Projects in classical physics**

Investigate the phase diagrams of one or two polymer chains: how the thermodynamical properties depend on parameters of the potential and parameters of the model itself. See if we can reproduce aggregation of proteins, one phenomenon that is responsible for some serious diseases. Investigate the behaviour of heteropolymers.

**Projects in quantum physics**

Electronic transport properties of polymers. Try to find a good model to describe electronic transport in our system. Investigate phase diagram: how the quantum observable (for example, conductivity) depends on parameters of the potential and parameters of the model. Check how “quantum” phases correlate with classical ones.

**If you are interested in programming**

You also can help to develop the code and learn some good programming practices which are useful far beyond the science itself.

The program is designed in a way to satisfy all requirements of modern software research engineering. The main code is written in C++11 and MPI. We use CMake, Google Test Environment, git and Doxygen. Now we are at the beginning of implementation of OpenCL to be able to take an advantages of not only CPU but GPU as well. In addition to the main code there are several utilities written in Python for visualisation.

**Contact**Anna Sinelnikova and Johan Nilsson

## Contact

- Programme Professor Materials Theory
- Olle Eriksson
- Avdelningsföreståndare
- Biplab Sanyal