Project acronym 0MSPIN
Project Spintronics based on relativistic phenomena in systems with zero magnetic moment
Researcher (PI) Tomas Jungwirth
Host Institution (HI) FYZIKALNI USTAV AV CR V.V.I
Country Czechia
Call Details Advanced Grant (AdG), PE3, ERC-2010-AdG_20100224
Summary The 0MSPIN project consists of an extensive integrated theoretical, experimental and device development programme of research opening a radical new approach to spintronics. Spintronics has the potential to supersede existing storage and memory applications, and to provide alternatives to current CMOS technology. Ferromagnetic matels used in all current spintronics applications may make it impractical to realise the full potential of spintronics. Metals are unsuitable for transistor and information processing applications, for opto-electronics, or for high-density integration. The 0MSPIN project aims to remove the major road-block holding back the development of spintronics in a radical way: removing the ferromagnetic component from key active parts or from the whole of the spintronic devices. This approach is based on exploiting the combination of exchange and spin-orbit coupling phenomena and material systems with zero macroscopic moment. The goal of the 0MSPIN is to provide a new paradigm by which spintronics can enter the realms of conventional semiconductors in both fundamental condensed matter research and in information technologies. In the central part of the proposal, the research towards this goal is embedded within a materials science project whose aim is to introduce into physics and microelectronics an entirely new class of semiconductors. 0MSPIN seeks to exploit three classes of material systems: (1) Antiferromagnetic bi-metallic 3d-5d alloys (e.g. Mn2Au). (2) Antiferromagnetic I-II-V semiconductors (e.g. LiMnAs). (3) Non-magnetic spin-orbit coupled semiconductors with injected spin-polarized currents (e.g. 2D III-V structures). Proof of concept devices operating at high temperatures will be fabricated to show-case new functionalities offered by zero-moment systems for sensing and memory applications, information processing, and opto-electronics technologies.
Summary
The 0MSPIN project consists of an extensive integrated theoretical, experimental and device development programme of research opening a radical new approach to spintronics. Spintronics has the potential to supersede existing storage and memory applications, and to provide alternatives to current CMOS technology. Ferromagnetic matels used in all current spintronics applications may make it impractical to realise the full potential of spintronics. Metals are unsuitable for transistor and information processing applications, for opto-electronics, or for high-density integration. The 0MSPIN project aims to remove the major road-block holding back the development of spintronics in a radical way: removing the ferromagnetic component from key active parts or from the whole of the spintronic devices. This approach is based on exploiting the combination of exchange and spin-orbit coupling phenomena and material systems with zero macroscopic moment. The goal of the 0MSPIN is to provide a new paradigm by which spintronics can enter the realms of conventional semiconductors in both fundamental condensed matter research and in information technologies. In the central part of the proposal, the research towards this goal is embedded within a materials science project whose aim is to introduce into physics and microelectronics an entirely new class of semiconductors. 0MSPIN seeks to exploit three classes of material systems: (1) Antiferromagnetic bi-metallic 3d-5d alloys (e.g. Mn2Au). (2) Antiferromagnetic I-II-V semiconductors (e.g. LiMnAs). (3) Non-magnetic spin-orbit coupled semiconductors with injected spin-polarized currents (e.g. 2D III-V structures). Proof of concept devices operating at high temperatures will be fabricated to show-case new functionalities offered by zero-moment systems for sensing and memory applications, information processing, and opto-electronics technologies.
Max ERC Funding
1 938 000 €
Duration
Start date: 2011-06-01, End date: 2016-05-31
Project acronym 2DNanoSpec
Project Nanoscale Vibrational Spectroscopy of Sensitive 2D Molecular Materials
Researcher (PI) Renato ZENOBI
Host Institution (HI) EIDGENOESSISCHE TECHNISCHE HOCHSCHULE ZUERICH
Country Switzerland
Call Details Advanced Grant (AdG), PE4, ERC-2016-ADG
Summary I propose to investigate the nanometer scale organization of delicate 2-dimensional molecular materials using nanoscale vibrational spectroscopy. 2D structures are of great scientific and technological importance, for example as novel materials (graphene, MoS2, WS2, etc.), and in the form of biological membranes and synthetic 2D-polymers. Powerful methods for their analysis and imaging with molecular selectivity and sufficient spatial resolution, however, are lacking. Tip-enhanced Raman spectroscopy (TERS) allows label-free spectroscopic identification of molecular species, with ≈10 nm spatial resolution, and with single molecule sensitivity for strong Raman scatterers. So far, however, TERS is not being carried out in liquids, which is the natural environment for membranes, and its application to poor Raman scatterers such as components of 2D polymers, lipids, or other membrane compounds (proteins, sugars) is difficult. TERS has the potential to overcome the restrictions of other optical/spectroscopic methods to study 2D materials, namely (i) insufficient spatial resolution of diffraction-limited optical methods; (ii) the need for labelling for all methods relying on fluorescence; and (iii) the inability of some methods to work in liquids. I propose to address a number of scientific questions associated with the spatial organization, and the occurrence of defects in sensitive 2D molecular materials. The success of these studies will also rely critically on technical innovations of TERS that notably address the problem of energy dissipation. This will for the first time allow its application to study of complex, delicate 2D molecular systems without photochemical damage.
Summary
I propose to investigate the nanometer scale organization of delicate 2-dimensional molecular materials using nanoscale vibrational spectroscopy. 2D structures are of great scientific and technological importance, for example as novel materials (graphene, MoS2, WS2, etc.), and in the form of biological membranes and synthetic 2D-polymers. Powerful methods for their analysis and imaging with molecular selectivity and sufficient spatial resolution, however, are lacking. Tip-enhanced Raman spectroscopy (TERS) allows label-free spectroscopic identification of molecular species, with ≈10 nm spatial resolution, and with single molecule sensitivity for strong Raman scatterers. So far, however, TERS is not being carried out in liquids, which is the natural environment for membranes, and its application to poor Raman scatterers such as components of 2D polymers, lipids, or other membrane compounds (proteins, sugars) is difficult. TERS has the potential to overcome the restrictions of other optical/spectroscopic methods to study 2D materials, namely (i) insufficient spatial resolution of diffraction-limited optical methods; (ii) the need for labelling for all methods relying on fluorescence; and (iii) the inability of some methods to work in liquids. I propose to address a number of scientific questions associated with the spatial organization, and the occurrence of defects in sensitive 2D molecular materials. The success of these studies will also rely critically on technical innovations of TERS that notably address the problem of energy dissipation. This will for the first time allow its application to study of complex, delicate 2D molecular systems without photochemical damage.
Max ERC Funding
2 311 696 €
Duration
Start date: 2017-09-01, End date: 2022-08-31
Project acronym 3-TOP
Project Exploring the physics of 3-dimensional topological insulators
Researcher (PI) Laurens Wigbolt Molenkamp
Host Institution (HI) JULIUS-MAXIMILIANS-UNIVERSITAT WURZBURG
Country Germany
Call Details Advanced Grant (AdG), PE3, ERC-2010-AdG_20100224
Summary Topological insulators constitute a novel class of materials where the topological details of the bulk band structure induce a robust surface state on the edges of the material. While transport data for 2-dimensional topological insulators have recently become available, experiments on their 3-dimensional counterparts are mainly limited to photoelectron spectroscopy. At the same time, a plethora of interesting novel physical phenomena have been predicted to occur in such systems.
In this proposal, we sketch an approach to tackle the transport and magnetic properties of the surface states in these materials. This starts with high quality layer growth, using molecular beam epitaxy, of bulk layers of HgTe, Bi2Se3 and Bi2Te3, which are the prime candidates to show the novel physics expected in this field. The existence of the relevant surface states will be assessed spectroscopically, but from there on research will focus on fabricating and characterizing nanostructures designed to elucidate the transport and magnetic properties of the topological surfaces using electrical, optical and scanning probe techniques. Apart from a general characterization of the Dirac band structure of the surface states, research will focus on the predicted magnetic monopole-like response of the system to an electrical test charge. In addition, much effort will be devoted to contacting the surface state with superconducting and magnetic top layers, with the final aim of demonstrating Majorana fermion behavior. As a final benefit, growth of thin high quality thin Bi2Se3 or Bi2Te3 layers could allow for a demonstration of the (2-dimensional) quantum spin Hall effect at room temperature - offering a road map to dissipation-less transport for the semiconductor industry.
Summary
Topological insulators constitute a novel class of materials where the topological details of the bulk band structure induce a robust surface state on the edges of the material. While transport data for 2-dimensional topological insulators have recently become available, experiments on their 3-dimensional counterparts are mainly limited to photoelectron spectroscopy. At the same time, a plethora of interesting novel physical phenomena have been predicted to occur in such systems.
In this proposal, we sketch an approach to tackle the transport and magnetic properties of the surface states in these materials. This starts with high quality layer growth, using molecular beam epitaxy, of bulk layers of HgTe, Bi2Se3 and Bi2Te3, which are the prime candidates to show the novel physics expected in this field. The existence of the relevant surface states will be assessed spectroscopically, but from there on research will focus on fabricating and characterizing nanostructures designed to elucidate the transport and magnetic properties of the topological surfaces using electrical, optical and scanning probe techniques. Apart from a general characterization of the Dirac band structure of the surface states, research will focus on the predicted magnetic monopole-like response of the system to an electrical test charge. In addition, much effort will be devoted to contacting the surface state with superconducting and magnetic top layers, with the final aim of demonstrating Majorana fermion behavior. As a final benefit, growth of thin high quality thin Bi2Se3 or Bi2Te3 layers could allow for a demonstration of the (2-dimensional) quantum spin Hall effect at room temperature - offering a road map to dissipation-less transport for the semiconductor industry.
Max ERC Funding
2 419 590 €
Duration
Start date: 2011-04-01, End date: 2016-03-31
Project acronym 3DIMAGE
Project 3D Imaging Across Lengthscales: From Atoms to Grains
Researcher (PI) Paul Anthony Midgley
Host Institution (HI) THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE
Country United Kingdom
Call Details Advanced Grant (AdG), PE4, ERC-2011-ADG_20110209
Summary "Understanding structure-property relationships across lengthscales is key to the design of functional and structural materials and devices. Moreover, the complexity of modern devices extends to three dimensions and as such 3D characterization is required across those lengthscales to provide a complete understanding and enable improvement in the material’s physical and chemical behaviour. 3D imaging and analysis from the atomic scale through to granular microstructure is proposed through the development of electron tomography using (S)TEM, and ‘dual beam’ SEM-FIB, techniques offering complementary approaches to 3D imaging across lengthscales stretching over 5 orders of magnitude.
We propose to extend tomography to include novel methods to determine atom positions in 3D with approaches incorporating new reconstruction algorithms, image processing and complementary nano-diffraction techniques. At the nanoscale, true 3D nano-metrology of morphology and composition is a key objective of the project, minimizing reconstruction and visualization artefacts. Mapping strain and optical properties in 3D are ambitious and exciting challenges that will yield new information at the nanoscale. Using the SEM-FIB, 3D ‘mesoscale’ structures will be revealed: morphology, crystallography and composition can be mapped simultaneously, with ~5nm resolution and over volumes too large to tackle by (S)TEM and too small for most x-ray techniques. In parallel, we will apply 3D imaging to a wide variety of key materials including heterogeneous catalysts, aerospace alloys, biomaterials, photovoltaic materials, and novel semiconductors.
We will collaborate with many departments in Cambridge and institutes worldwide. The personnel on the proposal will cover all aspects of the tomography proposed using high-end TEMs, including an aberration-corrected Titan, and a Helios dual beam. Importantly, a postdoc is dedicated to developing new algorithms for reconstruction, image and spectral processing."
Summary
"Understanding structure-property relationships across lengthscales is key to the design of functional and structural materials and devices. Moreover, the complexity of modern devices extends to three dimensions and as such 3D characterization is required across those lengthscales to provide a complete understanding and enable improvement in the material’s physical and chemical behaviour. 3D imaging and analysis from the atomic scale through to granular microstructure is proposed through the development of electron tomography using (S)TEM, and ‘dual beam’ SEM-FIB, techniques offering complementary approaches to 3D imaging across lengthscales stretching over 5 orders of magnitude.
We propose to extend tomography to include novel methods to determine atom positions in 3D with approaches incorporating new reconstruction algorithms, image processing and complementary nano-diffraction techniques. At the nanoscale, true 3D nano-metrology of morphology and composition is a key objective of the project, minimizing reconstruction and visualization artefacts. Mapping strain and optical properties in 3D are ambitious and exciting challenges that will yield new information at the nanoscale. Using the SEM-FIB, 3D ‘mesoscale’ structures will be revealed: morphology, crystallography and composition can be mapped simultaneously, with ~5nm resolution and over volumes too large to tackle by (S)TEM and too small for most x-ray techniques. In parallel, we will apply 3D imaging to a wide variety of key materials including heterogeneous catalysts, aerospace alloys, biomaterials, photovoltaic materials, and novel semiconductors.
We will collaborate with many departments in Cambridge and institutes worldwide. The personnel on the proposal will cover all aspects of the tomography proposed using high-end TEMs, including an aberration-corrected Titan, and a Helios dual beam. Importantly, a postdoc is dedicated to developing new algorithms for reconstruction, image and spectral processing."
Max ERC Funding
2 337 330 €
Duration
Start date: 2012-01-01, End date: 2017-12-31
Project acronym 3DNANOMECH
Project Three-dimensional molecular resolution mapping of soft matter-liquid interfaces
Researcher (PI) Ricardo Garcia
Host Institution (HI) AGENCIA ESTATAL CONSEJO SUPERIOR DEINVESTIGACIONES CIENTIFICAS
Country Spain
Call Details Advanced Grant (AdG), PE4, ERC-2013-ADG
Summary Optical, electron and probe microscopes are enabling tools for discoveries and knowledge generation in nanoscale sicence and technology. High resolution –nanoscale or molecular-, noninvasive and label-free imaging of three-dimensional soft matter-liquid interfaces has not been achieved by any microscopy method.
Force microscopy (AFM) is considered the second most relevant advance in materials science since 1960. Despite its impressive range of applications, the technique has some key limitations. Force microscopy has not three dimensional depth. What lies above or in the subsurface is not readily characterized.
3DNanoMech proposes to design, build and operate a high speed force-based method for the three-dimensional characterization soft matter-liquid interfaces (3D AFM). The microscope will combine a detection method based on force perturbations, adaptive algorithms, high speed piezo actuators and quantitative-oriented multifrequency approaches. The development of the microscope cannot be separated from its applications: imaging the error-free DNA repair and to understand the relationship existing between the nanomechanical properties and the malignancy of cancer cells. Those problems encompass the different spatial –molecular-nano-mesoscopic- and time –milli to seconds- scales of the instrument.
In short, 3DNanoMech aims to image, map and measure with picoNewton, millisecond and angstrom resolution soft matter surfaces and interfaces in liquid. The long-term vision of 3DNanoMech is to replace models or computer animations of bimolecular-liquid interfaces by real time, molecular resolution maps of properties and processes.
Summary
Optical, electron and probe microscopes are enabling tools for discoveries and knowledge generation in nanoscale sicence and technology. High resolution –nanoscale or molecular-, noninvasive and label-free imaging of three-dimensional soft matter-liquid interfaces has not been achieved by any microscopy method.
Force microscopy (AFM) is considered the second most relevant advance in materials science since 1960. Despite its impressive range of applications, the technique has some key limitations. Force microscopy has not three dimensional depth. What lies above or in the subsurface is not readily characterized.
3DNanoMech proposes to design, build and operate a high speed force-based method for the three-dimensional characterization soft matter-liquid interfaces (3D AFM). The microscope will combine a detection method based on force perturbations, adaptive algorithms, high speed piezo actuators and quantitative-oriented multifrequency approaches. The development of the microscope cannot be separated from its applications: imaging the error-free DNA repair and to understand the relationship existing between the nanomechanical properties and the malignancy of cancer cells. Those problems encompass the different spatial –molecular-nano-mesoscopic- and time –milli to seconds- scales of the instrument.
In short, 3DNanoMech aims to image, map and measure with picoNewton, millisecond and angstrom resolution soft matter surfaces and interfaces in liquid. The long-term vision of 3DNanoMech is to replace models or computer animations of bimolecular-liquid interfaces by real time, molecular resolution maps of properties and processes.
Max ERC Funding
2 499 928 €
Duration
Start date: 2014-02-01, End date: 2019-01-31
Project acronym 3SPIN
Project Three Dimensional Spintronics
Researcher (PI) Russell Paul Cowburn
Host Institution (HI) THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE
Country United Kingdom
Call Details Advanced Grant (AdG), PE3, ERC-2009-AdG
Summary Spintronics, in which both the spin and the charge of the electron are used, is one of the most exciting new disciplines to emerge from nanoscience. The 3SPIN project seeks to open a new research front within spintronics: namely 3-dimensional spintronics, in which magnetic nanostructures are formed into a 3-dimensional interacting network of unrivalled density and hence technological benefit. 3SPIN will explore early-stage science that could underpin 3-dimensional metallic spintronics. The thesis of the project is: that by careful control of the constituent nanostructure properties, a 3-dimensional medium can be created in which a large number of topological solitons can exist. Although hardly studied at all to date, these solitons should be stable at room temperature, extremely compact and easy to manipulate and propagate. This makes them potentially ideal candidates to form the basis of a new spintronics in which the soliton is the basic transport vector instead of electrical current. ¬3.5M of funding is requested to form a new team of 5 researchers who, over a period of 60 months, will perform computer simulations and experimental studies of solitons in 3-dimensional networks of magnetic nanostructures and develop a laboratory demonstrator 3-dimensional memory device using solitons to represent and store data. A high performance electron beam lithography system (cost 1M¬) will be purchased to allow state-of-the-art magnetic nanostructures to be fabricated with perfect control over their magnetic properties, thus allowing the ideal conditions for solitons to be created and controllably manipulated. Outputs from the project will be a complete understanding of the properties of these new objects and a road map charting the next steps for research in the field.
Summary
Spintronics, in which both the spin and the charge of the electron are used, is one of the most exciting new disciplines to emerge from nanoscience. The 3SPIN project seeks to open a new research front within spintronics: namely 3-dimensional spintronics, in which magnetic nanostructures are formed into a 3-dimensional interacting network of unrivalled density and hence technological benefit. 3SPIN will explore early-stage science that could underpin 3-dimensional metallic spintronics. The thesis of the project is: that by careful control of the constituent nanostructure properties, a 3-dimensional medium can be created in which a large number of topological solitons can exist. Although hardly studied at all to date, these solitons should be stable at room temperature, extremely compact and easy to manipulate and propagate. This makes them potentially ideal candidates to form the basis of a new spintronics in which the soliton is the basic transport vector instead of electrical current. ¬3.5M of funding is requested to form a new team of 5 researchers who, over a period of 60 months, will perform computer simulations and experimental studies of solitons in 3-dimensional networks of magnetic nanostructures and develop a laboratory demonstrator 3-dimensional memory device using solitons to represent and store data. A high performance electron beam lithography system (cost 1M¬) will be purchased to allow state-of-the-art magnetic nanostructures to be fabricated with perfect control over their magnetic properties, thus allowing the ideal conditions for solitons to be created and controllably manipulated. Outputs from the project will be a complete understanding of the properties of these new objects and a road map charting the next steps for research in the field.
Max ERC Funding
2 799 996 €
Duration
Start date: 2010-03-01, End date: 2016-02-29
Project acronym 4-TOPS
Project Four experiments in Topological Superconductivity.
Researcher (PI) Laurens Molenkamp
Host Institution (HI) JULIUS-MAXIMILIANS-UNIVERSITAT WURZBURG
Country Germany
Call Details Advanced Grant (AdG), PE3, ERC-2016-ADG
Summary Topological materials have developed rapidly in recent years, with my previous ERC-AG project 3-TOP playing a major role in this development. While so far no bulk topological superconductor has been unambiguously demonstrated, their properties can be studied in a very flexible manner by inducing superconductivity through the proximity effect into the surface or edge states of a topological insulator. In 4-TOPS we will explore the possibilities of this approach in full, and conduct a thorough study of induced superconductivity in both two and three dimensional HgTe based topological insulators. The 4 avenues we will follow are:
-SQUID based devices to investigate full phase dependent spectroscopy of the gapless Andreev bound state by studying their Josephson radiation and current-phase relationships.
-Experiments aimed at providing unambiguous proof of localized Majorana states in TI junctions by studying tunnelling transport into such states.
-Attempts to induce superconductivity in Quantum Hall states with the aim of creating a chiral topological superconductor. These chiral superconductors host Majorana fermions at their edges, which, at least in the case of a single QH edge mode, follow non-Abelian statistics and are therefore promising for explorations in topological quantum computing.
-Studies of induced superconductivity in Weyl semimetals, a completely unexplored state of matter.
Taken together, these four sets of experiments will greatly enhance our understanding of topological superconductivity, which is not only a subject of great academic interest as it constitutes the study of new phases of matter, but also has potential application in the field of quantum information processing.
Summary
Topological materials have developed rapidly in recent years, with my previous ERC-AG project 3-TOP playing a major role in this development. While so far no bulk topological superconductor has been unambiguously demonstrated, their properties can be studied in a very flexible manner by inducing superconductivity through the proximity effect into the surface or edge states of a topological insulator. In 4-TOPS we will explore the possibilities of this approach in full, and conduct a thorough study of induced superconductivity in both two and three dimensional HgTe based topological insulators. The 4 avenues we will follow are:
-SQUID based devices to investigate full phase dependent spectroscopy of the gapless Andreev bound state by studying their Josephson radiation and current-phase relationships.
-Experiments aimed at providing unambiguous proof of localized Majorana states in TI junctions by studying tunnelling transport into such states.
-Attempts to induce superconductivity in Quantum Hall states with the aim of creating a chiral topological superconductor. These chiral superconductors host Majorana fermions at their edges, which, at least in the case of a single QH edge mode, follow non-Abelian statistics and are therefore promising for explorations in topological quantum computing.
-Studies of induced superconductivity in Weyl semimetals, a completely unexplored state of matter.
Taken together, these four sets of experiments will greatly enhance our understanding of topological superconductivity, which is not only a subject of great academic interest as it constitutes the study of new phases of matter, but also has potential application in the field of quantum information processing.
Max ERC Funding
2 497 567 €
Duration
Start date: 2017-06-01, End date: 2022-05-31
Project acronym AAA
Project Adaptive Actin Architectures
Researcher (PI) Laurent Blanchoin
Host Institution (HI) CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
Country France
Call Details Advanced Grant (AdG), LS3, ERC-2016-ADG
Summary Although we have extensive knowledge of many important processes in cell biology, including information on many of the molecules involved and the physical interactions among them, we still do not understand most of the dynamical features that are the essence of living systems. This is particularly true for the actin cytoskeleton, a major component of the internal architecture of eukaryotic cells. In living cells, actin networks constantly assemble and disassemble filaments while maintaining an apparent stable structure, suggesting a perfect balance between the two processes. Such behaviors are called “dynamic steady states”. They confer upon actin networks a high degree of plasticity allowing them to adapt in response to external changes and enable cells to adjust to their environments. Despite their fundamental importance in the regulation of cell physiology, the basic mechanisms that control the coordinated dynamics of co-existing actin networks are poorly understood. In the AAA project, first, we will characterize the parameters that allow the coupling among co-existing actin networks at steady state. In vitro reconstituted systems will be used to control the actin nucleation patterns, the closed volume of the reaction chamber and the physical interaction of the networks. We hope to unravel the mechanism allowing the global coherence of a dynamic actin cytoskeleton. Second, we will use our unique capacity to perform dynamic micropatterning, to add or remove actin nucleation sites in real time, in order to investigate the ability of dynamic networks to adapt to changes and the role of coupled network dynamics in this emergent property. In this part, in vitro experiments will be complemented by the analysis of actin network remodeling in living cells. In the end, our project will provide a comprehensive understanding of how the adaptive response of the cytoskeleton derives from the complex interplay between its biochemical, structural and mechanical properties.
Summary
Although we have extensive knowledge of many important processes in cell biology, including information on many of the molecules involved and the physical interactions among them, we still do not understand most of the dynamical features that are the essence of living systems. This is particularly true for the actin cytoskeleton, a major component of the internal architecture of eukaryotic cells. In living cells, actin networks constantly assemble and disassemble filaments while maintaining an apparent stable structure, suggesting a perfect balance between the two processes. Such behaviors are called “dynamic steady states”. They confer upon actin networks a high degree of plasticity allowing them to adapt in response to external changes and enable cells to adjust to their environments. Despite their fundamental importance in the regulation of cell physiology, the basic mechanisms that control the coordinated dynamics of co-existing actin networks are poorly understood. In the AAA project, first, we will characterize the parameters that allow the coupling among co-existing actin networks at steady state. In vitro reconstituted systems will be used to control the actin nucleation patterns, the closed volume of the reaction chamber and the physical interaction of the networks. We hope to unravel the mechanism allowing the global coherence of a dynamic actin cytoskeleton. Second, we will use our unique capacity to perform dynamic micropatterning, to add or remove actin nucleation sites in real time, in order to investigate the ability of dynamic networks to adapt to changes and the role of coupled network dynamics in this emergent property. In this part, in vitro experiments will be complemented by the analysis of actin network remodeling in living cells. In the end, our project will provide a comprehensive understanding of how the adaptive response of the cytoskeleton derives from the complex interplay between its biochemical, structural and mechanical properties.
Max ERC Funding
2 349 898 €
Duration
Start date: 2017-09-01, End date: 2022-08-31
Project acronym ABACUS
Project Ab-initio adiabatic-connection curves for density-functional analysis and construction
Researcher (PI) Trygve Ulf Helgaker
Host Institution (HI) UNIVERSITETET I OSLO
Country Norway
Call Details Advanced Grant (AdG), PE4, ERC-2010-AdG_20100224
Summary Quantum chemistry provides two approaches to molecular electronic-structure calculations: the systematically refinable but expensive many-body wave-function methods and the inexpensive but not systematically refinable Kohn Sham method of density-functional theory (DFT). The accuracy of Kohn Sham calculations is determined by the quality of the exchange correlation functional, from which the effects of exchange and correlation among the electrons are extracted using the density rather than the wave function. However, the exact exchange correlation functional is unknown—instead, many approximate forms have been developed, by fitting to experimental data or by satisfying exact relations. Here, a new approach to density-functional analysis and construction is proposed: the Lieb variation principle, usually regarded as conceptually important but impracticable. By invoking the Lieb principle, it becomes possible to approach the development of approximate functionals in a novel manner, being directly guided by the behaviour of exact functional, accurately calculated for a wide variety of chemical systems. In particular, this principle will be used to calculate ab-initio adiabatic connection curves, studying the exchange correlation functional for a fixed density as the electronic interactions are turned on from zero to one. Pilot calculations have indicated the feasibility of this approach in simple cases—here, a comprehensive set of adiabatic-connection curves will be generated and utilized for calibration, construction, and analysis of density functionals, the objective being to produce improved functionals for Kohn Sham calculations by modelling or fitting such curves. The ABACUS approach will be particularly important in cases where little experimental information is available—for example, for understanding and modelling the behaviour of the exchange correlation functional in electromagnetic fields.
Summary
Quantum chemistry provides two approaches to molecular electronic-structure calculations: the systematically refinable but expensive many-body wave-function methods and the inexpensive but not systematically refinable Kohn Sham method of density-functional theory (DFT). The accuracy of Kohn Sham calculations is determined by the quality of the exchange correlation functional, from which the effects of exchange and correlation among the electrons are extracted using the density rather than the wave function. However, the exact exchange correlation functional is unknown—instead, many approximate forms have been developed, by fitting to experimental data or by satisfying exact relations. Here, a new approach to density-functional analysis and construction is proposed: the Lieb variation principle, usually regarded as conceptually important but impracticable. By invoking the Lieb principle, it becomes possible to approach the development of approximate functionals in a novel manner, being directly guided by the behaviour of exact functional, accurately calculated for a wide variety of chemical systems. In particular, this principle will be used to calculate ab-initio adiabatic connection curves, studying the exchange correlation functional for a fixed density as the electronic interactions are turned on from zero to one. Pilot calculations have indicated the feasibility of this approach in simple cases—here, a comprehensive set of adiabatic-connection curves will be generated and utilized for calibration, construction, and analysis of density functionals, the objective being to produce improved functionals for Kohn Sham calculations by modelling or fitting such curves. The ABACUS approach will be particularly important in cases where little experimental information is available—for example, for understanding and modelling the behaviour of the exchange correlation functional in electromagnetic fields.
Max ERC Funding
2 017 932 €
Duration
Start date: 2011-03-01, End date: 2016-02-29
Project acronym ABEL
Project "Alpha-helical Barrels: Exploring, Understanding and Exploiting a New Class of Protein Structure"
Researcher (PI) Derek Neil Woolfson
Host Institution (HI) UNIVERSITY OF BRISTOL
Country United Kingdom
Call Details Advanced Grant (AdG), LS9, ERC-2013-ADG
Summary "Recently through de novo peptide design, we have discovered and presented a new protein structure. This is an all-parallel, 6-helix bundle with a continuous central channel of 0.5 – 0.6 nm diameter. We posit that this is one of a broader class of protein structures that we call the alpha-helical barrels. Here, in three Work Packages, we propose to explore these structures and to develop protein functions within them. First, through a combination of computer-aided design, peptide synthesis and thorough biophysical characterization, we will examine the extents and limits of the alpha-helical-barrel structures. Whilst this is curiosity driven research, it also has practical consequences for the studies that will follow; that is, alpha-helical barrels made from increasing numbers of helices have channels or pores that increase in a predictable way. Second, we will use rational and empirical design approaches to engineer a range of functions within these cavities, including binding capabilities and enzyme-like activities. Finally, and taking the programme into another ambitious area, we will use the alpha-helical barrels to template other folds that are otherwise difficult to design and engineer, notably beta-barrels that insert into membranes to render ion-channel and sensor functions."
Summary
"Recently through de novo peptide design, we have discovered and presented a new protein structure. This is an all-parallel, 6-helix bundle with a continuous central channel of 0.5 – 0.6 nm diameter. We posit that this is one of a broader class of protein structures that we call the alpha-helical barrels. Here, in three Work Packages, we propose to explore these structures and to develop protein functions within them. First, through a combination of computer-aided design, peptide synthesis and thorough biophysical characterization, we will examine the extents and limits of the alpha-helical-barrel structures. Whilst this is curiosity driven research, it also has practical consequences for the studies that will follow; that is, alpha-helical barrels made from increasing numbers of helices have channels or pores that increase in a predictable way. Second, we will use rational and empirical design approaches to engineer a range of functions within these cavities, including binding capabilities and enzyme-like activities. Finally, and taking the programme into another ambitious area, we will use the alpha-helical barrels to template other folds that are otherwise difficult to design and engineer, notably beta-barrels that insert into membranes to render ion-channel and sensor functions."
Max ERC Funding
2 467 844 €
Duration
Start date: 2014-02-01, End date: 2019-01-31