ERC FUNDED PROJECTS

Polar materials, such as piezoelectrics and ferroelectrics are essential to our modern life, yet they are mostly developed by trial-and-error. Their properties overwhelmingly depend on the defects within them, the majority of which are hidden in the bulk. The road to better materials is via mapping these defects, but our best tool for it – piezoresponse force microscopy (PFM) – is limited to surfaces. 3D-PXM aims to revolutionize our understanding by measuring the local structure-property correlations around individual defects buried deep in the bulk. This is a completely new kind of microscopy enabling 3D maps of local strain and polarization (i.e. piezoresponse) with 10 nm resolution in mm-sized samples. It is novel, multi-scale and fast enough to capture defect dynamics in real time. Uniquely, it is a full-field method that uses a synthetic-aperture approach to improve both resolution and recover the image phase. This phase is then quantitatively correlated to local polarization and strain via a forward model. 3D-PXM combines advances in X-Ray optics, phase recovery and data analysis to create something transformative. In principle, it can achieve spatial resolution comparable to the best coherent X-Ray microscopy methods while being faster, used on larger samples, and without risk of radiation damage. For the first time, this opens the door to solving how defects influence bulk properties under real-life conditions. 3D-PXM focuses on three types of defects prevalent in polar materials: grain boundaries, dislocations and polar nanoregions. Individually they address major gaps in the state-of-the-art, while together making great strides towards fully understanding defects. This understanding is expected to inform a new generation of multi-scale models that can account for a material’s full heterogeneity. These models are the first step towards abandoning our tradition of trial-and-error, and with this comes the potential for a new era of polar materials.

1 496 941 €

Start date: 2019-01-01, End date: 2023-12-31

The project aims at a breakthrough in our understanding of stellar evolution, by combining advanced observations of stellar oscillations with state-of-the-art modelling of stars. This will largely be based on very extensive and precise data on stellar oscillations from the NASA Kepler mission launched in March 2009, but additional high-quality data will also be included. In particular, my group is developing the global SONG network for observations of stellar oscillations. These observational efforts will be supplemented by sophisticated modelling of stellar evolution, and by the development of asteroseismic tools to use the observations to probe stellar interiors. This will lead to a far more reliable determination of stellar ages, and hence ages of other astrophysical objects; it will compare the properties of the Sun with other stars and hence provide an understanding of the life history of the Sun; it will investigate the physical processes that control stellar properties, both at the level of the thermodynamical properties of stellar plasmas and the hydrodynamical instabilities that play a central role in stellar evolution; and it will characterize central stars in extra-solar planetary systems, determining the size and age of the star and hence constrain the evolution of the planetary systems. The Kepler data will be analysed in a large international collaboration coordinated by our group. The SONG network, which will become partially operational during the present project, will yield even detailed information about the conditions in the interior of stars, allowing tests of subtle but central aspects of the physics of stellar interiors. The projects involve the organization of a central data archive for asteroseismic data, at the Royal Library, Copenhagen.

2 498 149 €

Start date: 2011-04-01, End date: 2016-03-31

"One of the crucial formation channels of compact object binaries, including sources of gravitational waves, critically depends on catastrophic binary interactions accompanied by the loss of mass, angular momentum, and energy (""common envelope"" evolution - CEE). Despite its importance, CEE is perhaps the least understood major phase of binary star evolution and progress in this area is urgently needed to interpret observations from the new facilities (gravitational wave detectors, time-domain surveys). Recently, the dynamical phase of the CEE has been associated with a class of transient brightenings exhibiting slow expansion velocities and copious formation of dust and molecules (red transients - RT). A number of RT features, especially the long timescale of mass loss, challenge the existing CEE paradigm. Motivated by RT, I will use a new variant of magnetohydrodynamics to comprehensively examine the 3D evolution of CEE from the moment when the mass loss commences to the remnant phase. I expect to resolve the long timescales observed in RT, characterize binary stability in 3D with detailed microphysics, illuminate the fundamental problem of how is orbital energy used to unbind the common envelope in a regime that was inaccessible before, and break new ground on the amplification of magnetic fields during CEE. I will establish RT as an entirely new probe of the CEE physics by comparing my detailed theoretical predictions of light curves from different viewing angles, spectra, line profiles, and polarimetric signatures with observations of RT. I will accomplish this by coupling multi-dimensional moving mesh hydrodynamics with radiation, dust formation, and chemical reactions. Finally, I will examine the physical processes in RT remnants on timescales of years to centuries after the outburst to connect RT with the proposed merger products and to identify them in time-domain surveys. "

1 243 219 €

Start date: 2019-01-01, End date: 2023-12-31

The purpose of this proposal is to establish new fundamental insight of the reactivity and thereby the catalytic activity of oxides, nitrides, phosphides and sulfides (O-, N-, P-, S- ides) in the Cluster-Nanoparticle transition regime. We will use this insight to develop new catalysts through an interactive loop involving DFT simulations, synthesis, characterization and activity testing. The overarching objective is to make new catalysts that are efficient for production of solar fuels and chemicals to facilitate the implementation of sustainable energy, e.g. electrochemical hydrogen production and reduction of CO2 and N2 through both electrochemical and thermally activated processes. Recent research has identified why there is a lack of significant progress in developing new more active catalysts. Chemical scaling-relations exist among the intermediates, making it difficult to find a reaction pathway, which provides a flat potential energy landscape - a necessity for making the reaction proceed without large losses. My hypothesis is that going away from the conventional size regime, > 2 nm, one may break such chemical scaling-relations. Non-scalable behavior means that adding an atom results in a completely different reactivity. This drastic change could be even further enhanced if the added atom is a different element than the recipient particle, providing new freedom to control the reaction pathway. The methodology will be based on setting up a specifically optimized instrument for synthesizing such mass-selected clusters/nanoparticles. Thus far, researchers have barely explored this size regime. Only a limited amount of studies has been devoted to inorganic entities of oxides and sulfides; nitrides and phosphides are completely unexplored. We will employ atomic level simulations, synthesis, characterization, and subsequently test for specific reactions. This interdisciplinary loop will result in new breakthroughs in the area of catalyst material discovery.

2 500 000 €

Start date: 2017-09-01, End date: 2022-08-31