Scale-bridging computational design of multifunctional ferroelectric composites

• Applicant: Professorin Dr. Anna Grünebohm
• Subject Area: Synthesis and Properties of Functional Materials
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 412303109

In the last decade ferroelectric perovskites emerged as materials for sustainable energy technologies. In these materials the large couplings between polarization, temperature, stress and the external field give rise to exceptional functional responses. These responses can be utilized to harvest mechanical energy or temperature fluctuations as electric energy, in energy efficient solid-state cooling devices, and for short-term energy storage.All applications ask for large and reversible responses in a broad and suitable temperature range, large figures of merit and low losses. However, large responses are often restricted to small parameter ranges, and hysteresis as well as induced changes of the domain and defect structures result in irreversibilities and degeneration of the responses. This is diametral to highly efficient energy applications. Most existing high-performance materials are based on toxic Pb. Alternative systems based on available and sustainable materials are urgently needed. In this context, my group will open up the field of a controlled scale-bridging design of Pb-free composites with superior functional properties. Our goal is the simultaneous optimization of multiple responses with high technological impact.Our methods are scale-bridging simulations based on ab initio parametrization with high predictive power, which allow us to fundamentally understand and design the properties of materials systems.Our approach is the scale-bridging optimization of composite.We will address technological demands by the combination of (I) materials choice, (II) controlled use of inhomogeneities, (III) interfaces and (IV) composite morphologies, cf. graphical abstract.The unique feature is the exploration of the nano-scale domain structure for all these material modifications.

• DFG Programme: Independent Junior Research Groups