Chemical weathering is a central biogeochemical process that shapes the Earth’s Critical Zone (CZ), regulates the global carbon cycle and sets the pace for nutrient delivery to soils and ecosystems. Most knowledge on the rates and controls on chemical weathering are from laboratory experiments and from the short-term observation of modern soil and river systems. In contrast, little is known about past changes of chemical weathering over hundreds to thousands of years, which limits our understanding of how long-lasting human-climate-ecosystem interactions have impacted the CZ trajectories. Because of this knowledge gap, it is not possible to fully understand the response and feedbacks of the CZ to the climatic and environmental perturbations of the Holocene period, nor to predict their future evolution during the Anthropocene. To fill this gap, LAKE-SWITCH aims to produce new quantitative weathering records over 10^2-10^4 year timescales, with a temporal focus on the Holocene period. There are 3 main challenges: 1) developing quantitative proxies of chemical weathering, 2) calibrating these proxies for paleo-reconstructions, 3) measuring these proxies in paleo-archives of 10^2-10^4 year timescale integration. To provide these records, we will measure lithium and strontium isotopic proxies in lake detrital and authigenic – carbonates and biogenic silica – sediment archives. To calibrate these proxies and archives, we will use a source-to-sink approach and track weathering product pathways from soils, through rivers, to lake deposits. Then we will apply these proxies back in time in Holocene lake cores. As rapidly-eroding mountain dominate the global chemical erosion budget, we will focus on the study of the European Alps. New data from Alpine watersheds and lake records spanning gradients in erosion, runoff and land use will serve to quantify and model the impact of climate and human drivers on soil trajectories from the onset of the Holocene to the Anthropocene.

With more than 5300 exoplanets detected so far, it is clear that planet formation is a robust and efficient process. The current population of known exoplanets exhibits a wide diversity, both in nature (mass, radius) and in architecture: while giant planets can be found at large separations, the most common type of exoplanetary systems revealed by Kepler transits consist of chains of low-mass planets, super-Earths and mini-Neptunes, located close to their host stars. To understand the origin of this diversity, we need to explore the birth environment of the planets, namely the planet-forming protoplanetary disks, and to investigate their structure and evolution on both local and global scales. While considerable progress has recently been made in probing the disks on large scales (a few tens of astronomical units, au), little is known about the innermost regions (less than a few au). The IRYSS (Innermost Regions of Young Stellar Systems) project aims at deciphering the processes at play in the innermost regions of protoplanetary disks (PPDs). For the first time, we will provide a statistical view of the inner parts of a large sample of PPDs, thus bringing to light the main missing piece in our understanding of planet formation. The project builds on the unique synergy between the observational approaches developed by the partners, IPAG and IRAP, on national Research Infrastructures such as ESO/VLTI (with the PIONIER and GRAVITY interferometric instruments, largely developed at IPAG) and CFHT (with the ESPaDOnS and SPIRou spectropolarimeters, both developed at IRAP), in combination with the development of advanced physical models of the inner disk edge and of the accretion flows onto the central star. Benefiting from these world-class facilities, which are at the heart of the orientations of the call, we will conduct a multi-wavelength, multi-technique, and multi-scale investigation of the inner disk regions in a few tens of young stellar systems. We will explore the initial and environmental conditions that prevail at the time of planet formation by addressing three intrinsically interconnected pillars: 1) the morphological (asymmetry, vortex, dead zone) and physical (temperature, density) properties of the innermost scales of the protoplanetary disk, by spatially resolving at the sub-au level the near- and mid-infrared continuum emission with interferometry; 2) the magnetic star-disk interaction region, extending over a few stellar radii, and whose outer edge is thought to be the place where inwards migrating planets pile up, with spectropolarimetric observations and Zeeman-Doppler Imaging to derive the magnetic field topology and strength; 3) the dynamical timescales of the physical processes from a few days to months, by monitoring the variability of both the magnetic topology and the small-scale disk features. The combined analysis of these data sets arising from these two state-of-the-art observational techniques will put the world-leading French experts in a unique position to provide the stellar and exoplanet communities with legacy databases of magnetic maps, line profiles, inner rim positions and disk substructures. These are the key ingredients to relate the magnetic properties of young stars to the structure of their inner disk, and to investigate their evolution over periods as long as 10 years for some emblematic objects. As such, this legacy will provide access to a detailed overview of the innermost regions of nascent stellar systems and their disks where close-in planets form. Our team has access to all the ESO and CFHT Large Program and Guarantee Time observations to be exploited in the IRYSS project, and has developed during previous ERC-funded grants cutting-edge analysis and modeling tools required for their interpretation. We therefore gather the optimal expertise to yield major advances in this competitive field, supported by the appropriate workforce provided by this specific and quite timely ANR call.

The market introduction of high temperature wide bandgap power semiconductor devices with junction temperature exceeding 200°C significantly accelerates the trend towards high power density and severe ambient temperature electronics applications. Such evolution may have a great impact in aeronautics applications, especially with the development of More Electric Aircraft (MEA), since it can allow to reduce the mass and volume of power electronics systems. As a consequence, the aircraft operating cost can decrease. However, for electronics used under such harsh conditions, the package reliability and the heat evacuation are very critical issues. The goal of this project is to design and fabricate high performance double sided cooled power electronics modules with optimized thermomechanical properties. The assembly is based on copper joints and a copper heat sink and integrates several technological breakthroughs. Three main technological bricks will be deeply addressed in order to reach the target: 1) Synthesis of nanoporous copper films, either freestanding or directly deposited on metallized substrates with controlled microstructure: In order to limit the risks, three independent strategies will be investigated during the project: the synthesis of nanoporous copper free standing films using melt-spinning and chemical dealloying techniques, the direct on-substrate electroforming of copper-alloy followed by anodic dealloying, and the direct growth of nanoporous structures without any additional treatment by tuning electrolyte formulation and plating parameters. 2) Thermocompression of the nanoporous copper films for die attach: Conventional heating will be achieved at low pressure and in inert/reductive atmosphere. An alternative method based on laser induced fast heating will also be evaluated to thermocompress the nanoporous copper in air. Both solutions allow to limit the oxidation copper issues. The underlying physical mechanisms taking place during the thermocompression of the various morphologies and microstructures of nanoporous copper films will be in-depth investigated. The joint stability under electro-thermo-mechanical aging conditions will be evaluated. 3) Deposition of thick copper layers for substrate/heatsink assembly using electroforming process: A thick dense metal layer will be deposited on a designed sacrificial polymer preform allowing to create a wide range of complex shapes directly on the metallized substrate with low residual stresses. This technology combined to virtual prototyping will allow us to fabricate high performance heat sink patterns (liquid forced convection without phase change) in terms of high local heat transfer coefficient and low pressure drop. The thermal-hydraulic performances of the heat sinks will be analyzed with an experimental setup. The robustness of the assembly (substrate/heat-sink) under repetitive temperature variations will be also evaluated. Silicon Carbide (SiC) devices based power modules (inverter phase leg) using the aforementioned technological bricks will be realized and evaluated in the project. Electrical, thermal and robustness tests are planned to estimate the module performances. The COPPERPACK project will contribute to validate and push our concept from Technology Readiness Level (TRL) 2 up to a TRL 3-4 with a functional technological demonstrator.

Information technologies are at the cusp of another revolution triggered by the emergence of new generation of wireless telecommunication technologies and the promise of new paradigms through the quantum computer. This development requires the introduction of new materials for post CMOS technologies that offer new ultra low dissipation microwave functionalities, while remaining compatible with integration and nano-patterning. In this respect, magnetic garnets with a well-established track record of improving the performance of microwave or optical devices are prime candidates. HARMONY will demonstrate this by proof of principle in the form of an integrated analog coherent microwave converter between photon-magnon-phonon. So far the development of yttrium iron garnet (YIG) thin films for integrated solutions was hampered by the fact that high quality epitaxial growth could only be achieved on gadolinium gallium garnet (GGG) substrates. GGG, however, must be considered a matched material for both the phonon and photon character, which thus offers an energy leakage path and as a consequence prohibits the confinement of their microwave energy within the sole YIG layer. To overcome this problem, a new process developed by the group of G. Schmidt in Halle has allowed to fabricate free standing micron-size YIG beams with high magnon life time, hereby mainly avoiding the energy leakage through the substrate. These new objects have the potential to become game-changers for high-fidelity front-end telecom components operating at GHz frequencies. Furthermore, they can provide new tools for quantum information exchange between distant qbits also operating at GHz frequencies. HARMONY will initiate a technological breakthrough by providing a viable development path for integrating the coherent and efficient interconversion of information between photon-magnon-phonon on a chip. It builds on the tripartite hybridization process inside magnetic garnets that employs nested resonances of increasing finesse. HARMONY focuses on the fabrication of suspended YIG beams to remove technological road-blocks by the following goals: i) provide an efficient scheme to excite GHz phonons by magneto-elastic effects through the co-tuning of 3 cavities; ii) improve the energy efficiency with an ultra-low loss material that is isolated from the substrate for the highest finesse and iii) implement this in an integrated on-chip device. The objective of the project HARMONY will be to evaluate within a 3 years period, how these suspended garnet structures perform as microwave transducers. The project is designed as a collaboration between the group of Spintec, Néel and Halle. The synergy of their complementary track records will allow us to realize these ambitious goals. While coupling of magnons to microwave photons at low temperature will mainly be performed in Germany, the coupling of magnons to phonons will be performed in France. The micropatterning and YIG deposition is uniquely located in Halle while micromagnetic simulations and resonator design as well as characterization of all structures by FMR microscopy at room temperature is done at Spintec, matched by opto-mechanical surveys of the vibration pattern at Néel. The envisioned sequel of the HARMONY project is to extend the concept of coherent coupling to entanglement with whispering gallery optical modes.