2 PhD positions: Real structure of materials with local lattice instabilities

The research group of Prof. Simonov is looking for two highly motivated candidates with a strong interest in material development and characterization. The project will combine the experimental characterization of crystals on large-scale facilities and their computational modeling.

The positions are available from December 2023 onwards.

Our group focuses on understanding and controlling disorder in single crystals. Typically disorder is considered as a sign of crystal imperfection, but we find that often it is beneficial for functional properties and also gives rise to fascinating physics. 

The current project will focus on crystals in which disorder is driven by electron instabilities. These are chemically perfect crystals in which electrons have degenerate configurations and, as a result, occupy different states in different unit cells. Such structures show unusual physics, such as colossal magnetoresistance, and other forms of polaronic transport phenomena. In this project, you will develop novel approaches to experimentally probe such hidden states based on single crystal diffuse scattering, model them using coarse-graining of DFT calculations, and understand the influence of electronic disorder on their properties like colossal magnetoresistance or, in perspective, unconventional superconductivity.

Two projects are available:

In Project 1 you will grow single crystals of perovskite and pyrochlore oxides, characterize them using x-ray and neutron diffraction on large-scale synchrotron and spallation sources, analyze their diffuse scattering and model their average and local structure, measure their magnetic and transport properties and identify the relation between disordered structure and observed properties.

Project 2 will also involve experiments at large facilities but is mostly computational. You will develop code for processing and analyzing single crystal diffuse scattering data, and model crystal electronic structure using Density Functional Theory (DFT), and coarse-grain DFT to run large-scale atomic simulations of the real structure of disordered solids.

Project I

• MSc in Physics, Chemistry, Materials Science, Mathematics, Computer Science or related subjects
• Experience x-ray or neutron diffraction, crystal growth, DFT calculations, lattice dynamics and/or strong programming skills (python, C++)
• Motivated, proactive and creative

for Project II

• Masters or equivalent degree in mathematics, computer sciences, physics, chemistry or related disciplines
• Very good programming skills
• Experience and knowledge in the fields of DFT modelling, statistical mechanics, Monte Carlo modelling is an advantage

ETH Zurich is a family-friendly employer with excellent wokring conditions. You can look forward to an exciting working environment, cultural diversity and attractive offers and benefits.