The research of this RTG will focus on metamaterials, i.e. delicate structures produced by 3D printing that are perceived as a material in a component. The design of the internal structure enables tailored, sometimes extraordinary properties for applications in the mobility, medical and energy sectors. The investigations planned in D³ are aimed at both the mechanical performance and the sustainability of the new materials. The vision of D³ is to develop and apply a fully digital, data-driven approach to design metamaterials that is transferable to other material systems. The M3S group is involved tosupport mesoscale modeling and the description of patterns for inverse design

This project focuses on the development of a mesoscale framework to study positional ordering and defects on deformable surfaces by using different modeling approaches and develop their extension to non-flat domains. The amplitude expansion of the phase-field crystal model is considered to handle elasticity and plasticity at the mesoscale without resolving atoms but retaining details of the crystal structure. Orientational ordering and deformable interacting objects, e.g. cells in epithelial tissues, will be modeled by a multi-phase-field approach governed by Allen-Cahn type equations and coupling with director and Q-tensor fields. Formulations suitable for non-flat domains will be developed via a general graph formulation.

This project addresses the mesoscale modeling of crystalline systems. It builds on the phase-field crystal (PFC) model and its amplitude expansion (APFC), which provide convenient coarse-grained descriptions of crystalline structures. It aims at i) delivering novel theoretical tools that bridge micro- and macroscopic features while studying crystals accounting for real material properties, ii) overcoming limitations of current state-of-the-art theoretical approaches in this field through new and hybrid approaches, iii) enabling applications to technology-relevant crystalline systems and related open problems in materials science.

NARCISO "NAtuRal instability of semiConductors thIn SOlid films for sensing and photonic applications"is an interdisciplinary project merging physics, chemistry, material science, fluid dynamics, and photonics with a high potential for applications and industrial scale-up of the relevant results. We propose to exploit the natural instability of thin solid films (solid state dewetting of silicon and germanium, SSD) to form complex patterns and nano-architectures (e.g. monocrystalline atomically-smooth structures, disordered hyperuniform metamaterials) that cannot be implemented with conventional methods.

µSPIRE aims at establishing a technological platform for homo- and hetero- structure based photonic and electronic devices using the self-assembling of epitaxial crystals on patterned Si substrates. Emerging micro-electronic and photonic devices strongly require the integration on Si of a variety of semiconducting materials such as Ge, GaAs, in order to add novel functionalities to the Si platform. µSPIRE pursues this goal employing a novel deposition approach, which we termed vertical hetero-epitaxy (VHE), optimizied with the aid of simulations. VHE exploits the patterning of conventional Si substrates, in combination with epitaxial deposition, to attain the self-assembly of arrays of Ge and GaAs epitaxial micro-crystals elongated in the vertical direction, featuring structural and electronic properties unparalleled by “conventional” epitaxial growth.