Linköping University

"Discovered in 2011, MXenes are by far the youngest family of 2D materials known and thus the least understood. MXenes are so called because they are derived from the Mn+1AXn (or MAX) phases where M is an early transition metal, A is an A-group element (mostly 13 and 14), X is C and/or N. To convert the MAX phases to their MXenes, the A-layers – the vast majority of which are Al - are selectively etched using HF-containing solutions. The A-layers are replaced by surface terminations, T, (-O, -OH and –F) which is why their proper designation is Mn+1XnTx. In 2017, one of the PI's (IFM) of this proposal predicted and then synthesized quaternary compounds with the formula (M'2/3,M""1/3)2AlC, where M' and M'' are two metals, one of which is an early transition metal. What distinguishes these phases from all other MAX phases is the in-plane ordering of the M' and M"" atoms, which is why we are labelling them i-MAX phases. The same group established the existence of i-MAX phases with the chemical formula: (M2/3RE1/3)2AlC, where RE = Ce, Pr, Nd, Sm, Gd, Tb, Dy, Er, Ho, Tm and Lu. These phases were also predicted to be and indeed found to be magnetic. Members of a simultaneously discovered, similar layered family, with stoichiometry M4RE4Al7C3, were found to be ferromagnetic (Fig. 2b). Since all these phases are Al-containing, the Al should be readily selectively etched to create 2D RE-i-MXenes, where the RE elements are ordered in the basal planes. The goal of the proposed work is to fundamentally understand the electronic and magnetic properties of single RE-i-MXenes layers. The latter will be produced in two ways: i) mechanical exfoliation of large single crystals and, ii) chemical exfoliation/etching of powders. The ultimate objective is to deposit relatively large (100 µm2) single layers on SiO2/Si substrates and characterize them. The two approaches should result in different terminations, that in turn will elucidate the crucial role that surface terminations and etching induced defects play on the transport, and more importantly, magnetic properties. The work involves 4 labs: i) LMGP in Grenoble, is the only lab in the world that routinely produces large MAX single crystals. It will grow RE-i-MAX crystals. ii) INEEL, also in Grenoble, will mechanically exfoliate the crystals and, along with the UCL group in Louvain, will concentrate on processing devices and measuring the low temperature magnetic properties of both Re-i-MAX and RE-i-MXenes phases. iii) IFM in Sweden will be responsible for supplying high purity powders to the other partners and continuing in their trail blazing efforts to understand the magnetism of these phases by DFT calculations. iv) UCL will measure and simulate - using ab initio calculations - magneto-transport and vibrational (Raman) properties of both the Re-i-MAX and RE-i-MXenes, with a particular focus on the role of surface termination in the case of the latter. The possibility to significantly increase the palette of available of metallic/magnetic MXene 2D crystals is important in the perspective of ""full 2D"" electronic and spintronic devices, as they could be used both as interconnects with low electrical resistivities and low contact resistances. Most importantly if 2D single sheets are produced, such a major breakthrough can lead to spin injection/detection."

"As stated in the National Strategy for Research report (SNR, Action Plan 2016 , ANR Call), while presenting one of the five priorities of Challenge 3 ""Industrial Renewal"" (Priority 14 ""Design of new materials""): "" The products of the future will be more complex and mix several materials endowing final products with unique advantages (lightness, conductivity, ….). Combinations of basic components are becoming increasingly diverse. The forming and implementation processes of multi-materials … therefore pose a major challenge."" The FOGEL project is precisely proposed in this context, with the ambition to contribute to a better understanding of the phenomena guiding the structuring process of self-assembled architectures, based on a specific family of donor-acceptor two-component organogels. Organogels constitute a fascinating class of materials prepared through a bottom-up approach. These systems are indeed able to transduce a recognition phenomenon occuring at the molecular level, into a macroscopic network of well-defined one-dimensional entangled assemblies. These materials, based on the self-assembly of organic molecules (gelators) in a given solvent, have been subject to intensive studies, which are justified by reasonably simple syntheses of precursors, a good modularity and an easy implementation. Whereas they have been successfully applied in various areas, they nevertheless suffer from several handicaps which have notably hampered their use in the rapidly expanding field of organic electronics (photonics). On the one hand, rationalization of the gelation capacity of a given system is extremely delicate; secondly, they rely on assemblies which present defects which strongly affect their performance for electronic applications. In this context, spectacular breakthroughs were accomplished in the last few years, following an approach that is based on donor-acceptor (D-A) two-component organogels. The latter offer the possibility of combining both the intrinsic properties of both entities (e.g. optical / electronic), while relying on their D-A complementarity to generate a self-assembly by charge transfer. We recently described (2016) the preparation of systems based on this approach, by using organogelators featuring two or three photoactive pyrene (D) units. A considerable increase of the gelation capacity of one of these organogelators could be observed upon addition of various acceptors (A) and, remarkably, this effect could be observed for very low ratio of A/D, suggesting an original supramolecular polymerization process, still unknown for this class of gelators. Based on this innovative result, we propose to address through the FOGEL project, a comprehensive study covering the various facets of this very promising new approach. In particular, FOGEL will concentrate on the foundations guiding the nucleation and growth processes from such D-A gels, at both theoretical and experimental levels. The impact of various parameters (such as the A/D ratio) on their stability, on the morphology of the resulting microstructures and on their mechanical properties will be evaluated in order to optimize their implementation. The latter will allow preliminarily studies of their applicability for detection purposes (nitroaromatic compounds, explosives) as well as for charge transport (conductivity). Finally, these fundamental studies will be reinvested in developing new organogelators, in order to extend the scope of this innovative approach."

A quantum repeater-based internet can address our society’s need for secure communication and form the backbone for distributed quantum computing and sensing tasks [1,2]. In order to address the scalability challenge, three key technologies have yet to be demonstrated. On one side, quantum error correction [3] is required to maintain high quantum state fidelities in multi- node networks. On the other side, realistic rate improvements can be achieved by distributing quantum information with loss-resilient spin-entangled photonic cluster states [4,5]. Finally, these steps have to be integrated in robust, user-friendly and transportable systems. This project addresses these challenges using a solid-state system to demonstrate a quantum repeater, including spin-based quantum processing, and multi-photon state generation. Our advances in improving system robustness will be showcased by the integration into a real-field telecom fibre quantum link deployed over the French Riviera. The proposed quantum system is based on silicon vacancy (VSi) colour centres in semiconductor silicon carbide (SiC) [6–9]. Ground-breaking research from University of Stuttgart (US) and Linköping University (LIU) identified the system as truly unique as it combines all required features for demonstrating multi-spin- multi-photon quantum repeaters [6–9]. The expected technological advances are based on our waveguide integration of VSi centres [10] and fibre coupling with near-unity collection efficiency [11], which will be transferred into cryostats through synergies with the industrial partner Attocube Systems AG (AT). The collaboration between AT and the scientific partners will further lead to clear guidelines for next-generation compact, robust and transportable cryostat platforms, a critical requirement towards scalable quantum network architectures. The scientific goals comprise the improvement of our recent two-photon generation scheme [8] to higher photon numbers. We will also take advantage of the system’s uniquely high operation (T = 20 K) [12] to implement electron-nuclear spin control without the commonly observed heating-related issues. To make the VSi centre’s emission compatible with telecom networks, we will develop high- efficiency coherent quantum frequency converters [13,14] based on novel high index contrast lithium niobate (LN) devices, which has already been pioneered by the PIs from University of Iasi (UAIC) [15,16] and Université Côte d’Azur (INPHYNI). The unique synergies offered by the partners will allow us to embed an innovative and hybrid SiC-LN device into an inter-metropolitan fibre network. Besides the distribution of secret quantum keys, we will also show network-relevant quantum computational features, such as error correction and distribution of multi-photon states. Our quantum link will have a disruptive impact in the field of quantum communication and distributed quantum computing [17], thus providing substantial leaps forward towards establishing a European Quantum Internet. References 1. Wehner, S., et al., R. Science 362, 303 (2018). 2. Awschalom, et al., Nat. Photon. 12, 516 (2018). 3. Waldherr, G. et al. Nature 506, 204 (2014). 4. Borregaard, J. et al. Phys. Rev. X 10, 21071 (2020). 5. Michaels, C. P. et al. arXiv:2104.12619 (2021). 6. Nagy, R. et al. Phys. Rev. Appl. 9, 034022 (2018). 7. Nagy, R. et al. Nat. Commun. 10, 1954 (2019). 8. Morioka, N. et al. Nat. Commun. 11, 2516 (2020). 9. Nagy, R. et al. Appl. Phys. Lett. 118, 144003 (2021). 10. Babin, C. et al. arXiv2109.04737, Nat. Mater. to appear, (2021). 11. Bhaskar, M. K. et al. Nature 580, 60 (2020). 12. Udvarhelyi, P. et al. Phys. Rev. Appl. 13, 054017 (2020). 13. Tanzilli, S. et al. Nature 437, 116 (2005). 14. Kaiser, F. et al. Opt. Express 27, 25603 (2019). 15. Rambu, A. P. et al. J. Light. Technol. 36, 2675 (2018). 16. Rambu, A. P. et al. 8, 8 (2020). 17. Barz, S. et al. Science 335, 303 (2012).

The focus on particulate matter (PM2.5) mass reductions in UK air quality policy reflects the metrics measured for regulatory compliance. Epidemiological approaches have struggled to untangle the relative hazard of PM constituents within this mass, as well as co-pollutant gases, such as NO2, leading to the contention that all PM2.5 components must be treated as being equally harmful to human health. This makes little toxicological sense. The lack of a relative hazard ranking of PM constituents and co-emitted gases means that policy focuses on blunt strategies based on overall reductions in pollutant concentrations, rather than a refined focus on health relevant sources and components. This poses risks of unintended consequences, e.g. focusing on the largest contributors to PM2.5 for regulatory compliance, rather than the most harmful fractions, may fail to deliver predicted health benefits to the most vulnerable members of our society. In outdoor air this has remained unresolved for over 20-years, but further complexity is introduced by the heterogeneous indoor environment which must be considered in a complete picture of exposure. To address this major knowledge gap, the UK requires integration and focus of toxicological resource methodologies to identify the most hazardous fractions of indoor and outdoor PM and to elucidate the causal pathways contributing to disease development and exacerbation. Our proposed consortium brings together recognised UK expertise in atmospheric sciences, toxicology and biomedical sciences in a world-leading interdisciplinary collaboration to build an Air Pollution Hazard Identification Platform. This platform will deliver the capability to conduct controlled and characterised exposures to defined pollutant mixtures from different sources for in vitro, in vivo animal and human toxicological studies. We will use the large atmospheric simulation chamber at the University of Manchester to conduct experiments exposing human volunteers to diesel exhaust, woodsmoke, cooking emissions, secondary organic aerosol and NOx-enhanced mixtures, all at ambient atmospheric levels. These have been selected for their recognised substantial contributions to indoor and outdoor air pollution. The chamber exposures will be used as a reference and these experiments will be used to provide filtered samples of the PM for in vitro and transgenic animal exposures at the partner Institutions. Referenceable portable source units for all primary and secondary pollutant mixtures will be developed, characterised and deployed for in vitro and animal exposures to the full gas and particle mixture. Within the proposal, we will demonstrate the capability of the platform to elucidate the toxicological mechanisms involved in the neurological impacts of air pollution, though any health outcomes are accessible to the platform. The in vitro studies will be used to explore possible direct and indirect mechanisms for neuroinflammation and injury, identifying the molecular pathways associated with cellular activation. Using a unique panel of transgenic stress-reporter mouse lines, the stress response on exposure to the various pollutants will be tracked in a tissue and cell specific manner in vivo and provide a hazard ranking of the pollutants that can be related back to the in vitro molecular signatures. Repeat experiments with mouse lines susceptible to Alzheimer's disease will examine changes in these stress responses. Epigenetic DNA signatures will be examined in target tissues. A panel of healthy aged human subjects with a family history of increased dementia risk will provide biosamples and be subjected to cognitive tests on exposure to the different mixtures, further enabling their hazard ranking for correlation with the in vitro and animal studies. The mechanistic linkages between the animal and human exposure responses will be explored using candidate driven biomarker and untargeted metabolomic and epigenetic studies.