ERC FUNDED PROJECTS

The fundamental 3D-BioMat project aims at providing a biomineralization model to explain the formation of microscopic calcareous single-crystals produced by living organisms. Although these crystals present a wide variety of shapes, associated to various organic materials, the observation of a nanoscale granular structure common to almost all calcareous crystallizing organisms, associated to an extended crystalline coherence, underlies a generic biomineralization and assembly process. A key to building realistic scenarios of biomineralization is to reveal the crystalline architecture, at the mesoscale, (i. e., over a few granules), which none of the existing nano-characterization tools is able to provide. 3D-BioMat is based on the recognized PI’s expertise in the field of synchrotron coherent x-ray diffraction microscopy. It will extend the PI’s disruptive pioneering microscopy formalism, towards an innovative high-throughput approach able at giving access to the 3D mesoscale image of the crystalline properties (crystal-line coherence, crystal plane tilts and strains) with the required flexibility, nanoscale resolution, and non-invasiveness. This achievement will be used to timely reveal the generics of the mesoscale crystalline structure through the pioneering explorations of a vast variety of crystalline biominerals produced by the famous Pinctada mar-garitifera oyster shell, and thereby build a realistic biomineralization scenario. The inferred biomineralization pathways, including both physico-chemical pathways and biological controls, will ultimately be validated by comparing the mesoscale structures produced by biomimetic samples with the biogenic ones. Beyond deciphering one of the most intriguing questions of material nanosciences, 3D-BioMat may contribute to new climate models, pave the way for new routes in material synthesis and supply answers to the pearl-culture calcification problems.

1 966 429 €

Start date: 2017-03-01, End date: 2022-02-28

Active Matter systems, such as self-propelled colloids, violate time-reversal symmetry by producing entropy locally, typically converting fuel into mechanical motion at the particle scale. Other driven systems instead produce entropy because of global forcing by external fields, or boundary conditions that impose macroscopic fluxes (such as the momentum flux across a fluid sheared between moving parallel walls). Nonequilibrium statistical physics (NeSP) is the basic toolbox for both classes of system. In recent years, much progress in NeSP has stemmed from bottom-up work on driven systems. This has provided a number of exactly solved benchmark models, and extended approximation techniques to address driven non-ergodic systems, such as sheared glasses. Meanwhile, work on fluctuation theorems and stochastic thermodynamics have created profound, model-independent insights into dynamics far from equilibrium. More recently, the field of Active Matter has moved forward rapidly, leaving in its wake a series of generic and profound NeSP questions that now need answers: When is time-reversal symmetry, broken at the microscale, restored by coarse-graining? If it is restored, is an effective thermodynamic description is possible? How different is an active system's behaviour from a globally forced one? ADSNeSP aims to distil from recent Active Matter research such fundamental questions; answer them first in the context of specific models and second in more general terms; and then, using the tools and insights gained, shed new light on longstanding problems in the wider class of driven systems. I believe these new tools and insights will be substantial, because local activity takes systems far from equilibrium in a conceptually distinct direction from most types of global driving. By focusing on general principles and on simple models of activity, I seek to create a new vantage point that can inform, and potentially transform, wider areas of statistical physics.

2 043 630 €

Start date: 2017-10-01, End date: 2022-09-30

While amorphous solids constitute most of the solid matter found in Nature, their understanding is much poorer than for crystalline solids, at the point that most solid state textbooks are entirely focused on crystals. The reason underlying this uncomfortable situation is that amorphous solids display all kind of anomalies with respect to a simple description in terms of phonon excitations around a perfect lattice. In particular, they display an excess of low-frequency vibrational modes, their thermodynamic and transport coefficients behave differently from crystals, they respond non-linearly to arbitrarily small strains, and have highly cooperative dynamics. Traditionally, each of these aspects has been studied independently of the others, by almost distinct communities, and in terms of microscopic elements that are specific to a given material. The objective of this proposal is to take a different approach and seek a universal explanation of all the anomalies of amorphous solids, in terms of criticality associated with a new phase transition between two distinct glass phases. This goal is both ambitious and reachable. It is reachable because such a phase transition has just been theoretically predicted to exist on rigorous grounds, in an abstract limit of infinite spatial dimensions; its existence allows one to compute the critical exponents of jamming, in strikingly good agreement with numerical simulations; and the transition has been observed numerically in a realistic model of glass. It is ambitious because it requires to firmly establish the universal nature of the transition, and connect it to the experimentally observed anomalies through concrete analytical and numerical calculations, which will open the way to a direct experimental test. Both tasks require solving a number of difficult conceptual and technical problems. But, if successful, this project could lead to a revolution in our understanding of amorphous solid matter.

1 362 125 €

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

Phonons (quanta of vibration) play a major role in many of the physical properties of condensed matter. One of the most striking features of acoustic phonons is their ability to interact with virtually any other excitation in solids. Recent progress in the design, fabrication and control of nanomechanical systems has paved the way to explore new frontiers in the classical and quantum worlds. Devices based on semiconductor quantum dots (QDs) have been recently demonstrated to perform as near-ideal single photon sources, a very promising platform for developing a solid-state quantum network. The phonon engineering, however, remains an unexplored knob in the quantum information toolbox. The goal of this project is to explore new horizons in nanophononics by developing novel phononic networks with full control on the phonon dynamics, and unprecedented structures capable of acoustically interact with single QDs, bridging the gap between nanophononics and semiconductor QD quantum optics. AlGaAs based semiconductor cavities are capable of confining simultaneously photons and phonons. The building blocks of the proposed research are semiconductor pillar microcavities and single QDs deterministically positioned to maximize their interaction with the confined electromagnetic and elastic fields. To achieve our main goal we set three major objectives: 1) To develop novel one- and three-dimensional optophononic resonators and develop appropriate phononic measuring techniques; 2) To engineer nanophononic networks working in the tens-of-GHz range; and 3) To demonstrate first phonon cavity quantum electrodynamics phenomena for a single artificial atom coupled to a phononic cavity. Shaping the phononic environment opens exciting perspectives for solid state quantum applications, by providing a full control over the main source of decoherence and actually using it as a powerful resource to eventually transfer the quantum information.

1 499 375 €

Start date: 2017-02-01, End date: 2022-01-31

Molecular materials are ubiquitous, encompassing smart phone displays, plastic electronics and the molecular machinery of photosynthesis. Many of these remarkable uses depend on interactions between the molecules. Until now these interactions have been electric in character, and have been dictated by how electric charge is distributed over the molecules. PHOTMAT will transform the world of molecular materials by adding a new ingredient – photons. I will fuse photons and molecules together to create new hybrid states – part molecule and part photon – that are dramatically different from those of the constituent molecules and photons. The idea of coupling molecules with photons is a radical new approach with implications that reach across physics, quantum information, chemistry, materials science, nanotechnology and biology. I propose a pioneering research programme that will catalyse the transition from embryonic early results to the creation of a new conceptual framework to unveil a new frontier in nanoscience and nanotechnology. We will perform new experiments that will provide clear proof-of-principle demonstrations of the incredible opportunities opened up by coupling molecules with photons. As examples, we will show how the range over which energy (excitons) can be transport may be extended by a factor of 1000, and we will show how the process of photosynthesis can be modified and controlled. This research has enormous potential, from transforming artificial photosynthesis for clean fuel production to inspiring a new generation of molecular metamaterials. My goal is to explore the rich array of possibilities that arise when photons are made an integral part of molecular materials. At present much of the underlying physics is unclear and controversial. I will resolve the important open questions and show how photonic coupling of molecules leads to new molecular materials, new ways to control chemical and biological processes, and a new type of nanophotonics.

2 447 699 €

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

One of the most active challenges of modern solid state physics and chemistry is harnessing the unique and varied physical properties of transition-metal oxides. From improved electrodes for solar cells to loss-less transmission of power, these compounds hold the potential to transform our daily lives. Subtle collective quantum states underpin their diverse properties. These complicate their physical understanding but render them extremely sensitive to their local crystalline environment, offering enormous potential to tune their functional behaviour. To date, the vast majority of work has focussed on transition-metal oxides based around cubic “perovskite” building blocks. In contrast, exploiting the layered traingular network of the delafossite structure, the QUESTDO project aims to establish delafossite oxides as a completely novel class of interacting electron system with properties and potential not known in more established systems. Its scope bridges three of the most important current themes in condensed matter, investigating and controlling the delicate interplay of (i) frustrated triangular and honeycomb lattice geometries, (ii) interacting electrons, and (iii) effects of strong spin-orbit interactions. It brings together advanced spectroscopic measurement with precise materials fabrication. Through these studies, QUESTDO promises critical new insight on the quantum many-body problem in solids, and will advance our understanding and demonstrate atomic-scale control of the physical properties of delafossites. Ultimately, it seeks to establish new design methodologies for the targeted creation of emergent and topological phases in this little-studied family of transition-metal oxides, paving the route for their further study and ultimate application.

1 999 825 €

Start date: 2017-01-01, End date: 2021-12-31

Spintronics is motivated by the quest for the next-generation beyond-Moore electronics. The conventional approach that is based on single-electron spin currents does, however, not solve the thermodynamic bottleneck that is caused by the dissipation associated with moving electrons. A revolutionary new approach to electronics is based on information processing and transfer by means of magnons, i.e., quanta of the collective spin-wave excitations in magnets, so that the electrons do not move at all. On top of this application perspective, magnons give rise to completely new physical phenomena that arise due to magnonic collective effects and that do not fit the paradigm of single-electron spintronics. This shift from single-electron to collective degrees of freedom to carry spin current – in large part substantiated by a 2015 experimental breakthrough involving the PI – calls for the formulation of a new basic model that includes these novel collective phenomena on equal footing with single-particle spin currents. It is the central and unifying scientific goal of this theoretical-physics proposal to develop this model. We focus on three material systems: ferromagnetic insulators, ferromagnetic metals, and antiferromagnets, and for each of these the objective is to bring out the new physics that arises due to i) coupled spin-heat transport in the linear-response regime, ii) collective effects in spin valves, and iii) magnon Bose-Einstein condensation and spin superfluidity. The latter paves the way for “magnon superspintronics”, the integration of room-temperature spin superfluidity with spintronics. In terms of methodology the proposed research spans the spectrum from phenomenological hydrodynamic theory to evaluation of the various bulk and interface parameters from microscopic descriptions. Our recent work gives us, combined with our background in cold-atom systems, a head start to carry out the proposed research.

1 617 500 €

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