PhD student (m/f/d) physics, materials science
Leibniz Institute for Crystal Growth (IKZ), Berlin
The Leibniz-Institut für Kristallzüchtung (IKZ) is a leading research institution in the area of science & technology as well as service & transfer of crystalline materials. Our goal is to enable solutions for urgent societal challenges (e.g. communication, artificial intelligence, climate protection, health etc.). by modern electronic & photonic technologies. The work covers the full spectrum from basic over applied research up to pre-industrial development and is performed in collaboration with national and international partners from university, academy and industry. The institute is part of the
Forschungsverbund Berlin (https://www.fv-berlin.de/) and a member of the Leibniz Association www.leibniz-gemeinschaft.de. You can find more details on the institute webpage: www.ikz-berlin.de.
The Leibniz-Institut für Kristallzüchtung currently offers a
PhD student (m/f/d)
for the topic “Investigation of atomic and microscopic mechanisms of electromechanical coupling in uniaxial ferroelectrics”.
Electromechanical coupling is the ability of some solids to convert mechanical and electrical energies into one another. This physical phenomenon is of huge academic and industrial interest. Perovskite oxides ferroelectrics, usually lead-based, are currently the largest group of industrially relevant electromechanically active materials and used in pressure sensors, actuators, transducers, etc.
Fundamental knowledge of the structural mechanisms behind electromechanical coupling will allow for their systematic exploitation and go beyond the empirical approaches to optimize the functional materials properties. A detailed study of these fundamental mechanisms in industrially relevant materials is generally hindered by the additional presence of ferroelasticity. Uniaxial, ferroelectric single crystals, on the other hand, are free from these ferroelastic domains and therefore more suitable to analyze the structural response under external electric field.
This project aims for a detailed understanding of the role of purely ferroelectric domains in electromechanical coupling. These domains form to balance energy contributions from internal stresses and electric fields. In some materials, this can lead to anomalous enhancement of the electromechanical coupling. The objective is to quantify the crystallographic and domain-related changes in such materials for any state along the ferroelectric hysteresis loop. Furthermore, the concept of electrostriction as origin of piezoelectricity in polar materials will be explored and tested.
The PhD student will focus on the characterization of the structure of single-crystals subjected to time-dependent electric fields. Uniaxial ferroelectrics grown by dedicated IKZ groups are available for this study. The work involves time- and field-dependent X-ray diffraction (XRD) measurements both in IKZ labs and synchrotron radiation sources such as the ESRF, DESY or BESSY. Spatially resolved characterization on the microscale will be performed to study the influence of domain walls on elastic strain and polarization fields. The work will also include complementary characterization by laser interferometry and piezo-force microscopy (PFM) at IKZ. The project will be carried out in collaboration with a group at Tel-Aviv University (TAU) and regular scientific exchange is pivotal for success. This will also involve joint meetings and joint experiments at synchrotron sources.
- MSc degree in physics, materials science, or in a related discipline
- Basic knowledge of programming in ideally in Python, Matlab or C
- Work in a team of passionate scientists, technicians and students
- Good knowledge of the English language. A basic knowledge of German is beneficial.
Prior experience in the following fields is an asset to your application:
- Hands-on experience in single-crystal X-ray diffraction (high resolution or structure determination) for bulk or thin-films characterization
- Any experience in the usage of synchrotron radiation
- Electrical measurements (I-V / P-E loops) and electrical circuitry
- Education in crystallography
What we offer
The position is limited to three years, an extension for another year is possible. Payment is according to TVöD Bund (75 %) (Treaty for German public service) including the usual social benefits (30 vacation days in a 5-day week, flexible working hours). The IKZ is an equal opportunity employer and actively supports reconciliation of work and family life. There is equality for applicants of all genders. Qualified women are especially encouraged to apply. Among equally qualified applicants, preference will be given to disabled candidates.
For information about the project please contact: Dr. Carsten Richter, Tel. +49(0)30-6392-2859, carsten.richter(at)ikz-berlin.de
Have we aroused your interest?
Then apply with a letter of motivation, curriculum vitae and all relevant certificates. Please, send your application here. Applications will be accepted until the position is filled.
We look forward to receiving your application!