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 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 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 ABCvolume
Project The ABC of Cell Volume Regulation
Researcher (PI) Berend Poolman
Host Institution (HI) RIJKSUNIVERSITEIT GRONINGEN
Country Netherlands
Call Details Advanced Grant (AdG), LS1, ERC-2014-ADG
Summary Cell volume regulation is crucial for any living cell because changes in volume determine the metabolic activity through e.g. changes in ionic strength, pH, macromolecular crowding and membrane tension. These physical chemical parameters influence interaction rates and affinities of biomolecules, folding rates, and fold stabilities in vivo. Understanding of the underlying volume regulatory mechanisms has immediate application in biotechnology and health, yet these factors are generally ignored in systems analyses of cellular functions.
My team has uncovered a number of mechanisms and insights of cell volume regulation. The next step forward is to elucidate how the components of a cell volume regulatory circuit work together and control the physicochemical conditions of the cell.
I propose construction of a synthetic cell in which an osmoregulatory transporter and mechanosensitive channel form a minimal volume regulatory network. My group has developed the technology to reconstitute membrane proteins into lipid vesicles (synthetic cells). One of the challenges is to incorporate into the vesicles an efficient pathway for ATP production and maintain energy homeostasis while the load on the system varies. We aim to control the transmembrane flux of osmolytes, which requires elucidation of the molecular mechanism of gating of the osmoregulatory transporter. We will focus on the glycine betaine ABC importer, which is one of the most complex transporters known to date with ten distinct protein domains, transiently interacting with each other.
The proposed synthetic metabolic circuit constitutes a fascinating out-of-equilibrium system, allowing us to understand cell volume regulatory mechanisms in a context and at a level of complexity minimally needed for life. Analysis of this circuit will address many outstanding questions and eventually allow us to design more sophisticated vesicular systems with applications, for example as compartmentalized reaction networks.
Summary
Cell volume regulation is crucial for any living cell because changes in volume determine the metabolic activity through e.g. changes in ionic strength, pH, macromolecular crowding and membrane tension. These physical chemical parameters influence interaction rates and affinities of biomolecules, folding rates, and fold stabilities in vivo. Understanding of the underlying volume regulatory mechanisms has immediate application in biotechnology and health, yet these factors are generally ignored in systems analyses of cellular functions.
My team has uncovered a number of mechanisms and insights of cell volume regulation. The next step forward is to elucidate how the components of a cell volume regulatory circuit work together and control the physicochemical conditions of the cell.
I propose construction of a synthetic cell in which an osmoregulatory transporter and mechanosensitive channel form a minimal volume regulatory network. My group has developed the technology to reconstitute membrane proteins into lipid vesicles (synthetic cells). One of the challenges is to incorporate into the vesicles an efficient pathway for ATP production and maintain energy homeostasis while the load on the system varies. We aim to control the transmembrane flux of osmolytes, which requires elucidation of the molecular mechanism of gating of the osmoregulatory transporter. We will focus on the glycine betaine ABC importer, which is one of the most complex transporters known to date with ten distinct protein domains, transiently interacting with each other.
The proposed synthetic metabolic circuit constitutes a fascinating out-of-equilibrium system, allowing us to understand cell volume regulatory mechanisms in a context and at a level of complexity minimally needed for life. Analysis of this circuit will address many outstanding questions and eventually allow us to design more sophisticated vesicular systems with applications, for example as compartmentalized reaction networks.
Max ERC Funding
2 247 231 €
Duration
Start date: 2015-07-01, End date: 2020-06-30
Project acronym ACTINONSRF
Project MAL: an actin-regulated SRF transcriptional coactivator
Researcher (PI) Richard Treisman
Host Institution (HI) THE FRANCIS CRICK INSTITUTE LIMITED
Country United Kingdom
Call Details Advanced Grant (AdG), LS1, ERC-2010-AdG_20100317
Summary MAL: an actin-regulated SRF transcriptional coactivator
Recent years have seen a revitalised interest in the role of actin in nuclear processes, but the molecular mechanisms involved remain largely unexplored. We will elucidate the molecular basis for the actin-based control of the SRF transcriptional coactivator, MAL. SRF controls transcription through two families of coactivators, the actin-binding MRTFs (MAL, Mkl2), which couple its activity to cytoskeletal dynamics, and the ERK-regulated TCFs (Elk-1, SAP-1, Net). MAL subcellular localisation and transcriptional activity responds to signal-induced changes in G-actin concentration, which are sensed by its actin-binding N-terminal RPEL domain. Members of a second family of RPEL proteins, the Phactrs, also exhibit actin-regulated nucleocytoplasmic shuttling. The proposal addresses the following novel features of actin biology:
¿ Actin as a transcriptional regulator
¿ Actin as a signalling molecule
¿ Actin-binding proteins as targets for regulation by actin, rather than regulators of actin function
We will analyse the sequences and proteins involved in actin-regulated nucleocytoplasmic shuttling, using structural biology and biochemistry to analyse its control by changes in actin-RPEL domain interactions. We will characterise the dynamics of shuttling, and develop reporters for changes in actin-MAL interaction for analysis of pathway activation in vivo. We will identify genes controlling MAL itself, and the balance between the nuclear and cytoplasmic actin pools. The mechanism by which actin represses transcriptional activation by MAL in the nucleus, and its relation to MAL phosphorylation, will be elucidated. Finally, we will map MRTF and TCF cofactor recruitment to SRF targets on a genome-wide scale, and identify the steps in transcription controlled by actin-MAL interaction.
Summary
MAL: an actin-regulated SRF transcriptional coactivator
Recent years have seen a revitalised interest in the role of actin in nuclear processes, but the molecular mechanisms involved remain largely unexplored. We will elucidate the molecular basis for the actin-based control of the SRF transcriptional coactivator, MAL. SRF controls transcription through two families of coactivators, the actin-binding MRTFs (MAL, Mkl2), which couple its activity to cytoskeletal dynamics, and the ERK-regulated TCFs (Elk-1, SAP-1, Net). MAL subcellular localisation and transcriptional activity responds to signal-induced changes in G-actin concentration, which are sensed by its actin-binding N-terminal RPEL domain. Members of a second family of RPEL proteins, the Phactrs, also exhibit actin-regulated nucleocytoplasmic shuttling. The proposal addresses the following novel features of actin biology:
¿ Actin as a transcriptional regulator
¿ Actin as a signalling molecule
¿ Actin-binding proteins as targets for regulation by actin, rather than regulators of actin function
We will analyse the sequences and proteins involved in actin-regulated nucleocytoplasmic shuttling, using structural biology and biochemistry to analyse its control by changes in actin-RPEL domain interactions. We will characterise the dynamics of shuttling, and develop reporters for changes in actin-MAL interaction for analysis of pathway activation in vivo. We will identify genes controlling MAL itself, and the balance between the nuclear and cytoplasmic actin pools. The mechanism by which actin represses transcriptional activation by MAL in the nucleus, and its relation to MAL phosphorylation, will be elucidated. Finally, we will map MRTF and TCF cofactor recruitment to SRF targets on a genome-wide scale, and identify the steps in transcription controlled by actin-MAL interaction.
Max ERC Funding
1 889 995 €
Duration
Start date: 2011-10-01, End date: 2017-09-30
Project acronym ADEQUATE
Project Advanced optoelectronic Devices with Enhanced QUAntum efficiency at THz frEquencies
Researcher (PI) Carlo Sirtori
Host Institution (HI) UNIVERSITE PARIS DIDEROT - PARIS 7
Country France
Call Details Advanced Grant (AdG), PE3, ERC-2009-AdG
Summary The aim of this project is the realisation of efficient mid-infrared and THz optoelectronic emitters. This work is motivated by the fact that the spontaneous emission in this frequency range is characterized by an extremely long lifetime when compared to non-radiative processes, giving rise to devices with very low quantum efficiency. To this end we want to develop hybrid light-matter systems, already well known in quantum optics, within optoelectronics devices, that will be driven by electrical injection. With this project we want to extend the field of optoelectronics by introducing some of the concepts of quantum optic, particularly the light-matter strong coupling, into semiconductor devices. More precisely this project aims at the implementation of novel optoelectronic emitters operating in the strong coupling regime between an intersubband excitation of a two-dimensional electron gas and a microcavity photonic mode. The quasiparticles issued from this coupling are called intersubband polaritons. The major difficulties and challenges of this project, do not lay in the observation of these quantum effects, but in their exploitation for a specific function, in particular an efficient electrical to optical conversion. To obtain efficient quantum emitters in the THz frequency range we will follow two different approaches: - In the first case we will try to exploit the additional characteristic time of the system introduced by the light-matter interaction in the strong (or ultra-strong) coupling regime. - The second approach will exploit the fact that, under certain conditions, intersubband polaritons have a bosonic character; as a consequence they can undergo stimulated scattering, giving rise to polaritons lasers as it has been shown for excitonic polaritons.
Summary
The aim of this project is the realisation of efficient mid-infrared and THz optoelectronic emitters. This work is motivated by the fact that the spontaneous emission in this frequency range is characterized by an extremely long lifetime when compared to non-radiative processes, giving rise to devices with very low quantum efficiency. To this end we want to develop hybrid light-matter systems, already well known in quantum optics, within optoelectronics devices, that will be driven by electrical injection. With this project we want to extend the field of optoelectronics by introducing some of the concepts of quantum optic, particularly the light-matter strong coupling, into semiconductor devices. More precisely this project aims at the implementation of novel optoelectronic emitters operating in the strong coupling regime between an intersubband excitation of a two-dimensional electron gas and a microcavity photonic mode. The quasiparticles issued from this coupling are called intersubband polaritons. The major difficulties and challenges of this project, do not lay in the observation of these quantum effects, but in their exploitation for a specific function, in particular an efficient electrical to optical conversion. To obtain efficient quantum emitters in the THz frequency range we will follow two different approaches: - In the first case we will try to exploit the additional characteristic time of the system introduced by the light-matter interaction in the strong (or ultra-strong) coupling regime. - The second approach will exploit the fact that, under certain conditions, intersubband polaritons have a bosonic character; as a consequence they can undergo stimulated scattering, giving rise to polaritons lasers as it has been shown for excitonic polaritons.
Max ERC Funding
1 761 000 €
Duration
Start date: 2010-05-01, End date: 2015-04-30
Project acronym ADMIRE
Project Atomic-scale Design of Majorana states and their Innovative Real-space Exploration
Researcher (PI) Roland WIESENDANGER
Host Institution (HI) UNIVERSITAET HAMBURG
Country Germany
Call Details Advanced Grant (AdG), PE3, ERC-2017-ADG
Summary Fault-tolerant topological quantum computation has become one of the most exciting research directions in modern condensed matter physics. As a key operation the braiding of non-Abelian anyons has been proposed theoretically. Such exotic quasiparticles can be realized as zero-energy Majorana bound states at the ends of one-dimensional magnetic nanowires in proximity to s-wave superconductors in the presence of high spin-orbit coupling. In contrast to previous attempts to realize such systems experimentally, based on the growth of semiconducting nanowires or the self-assembly of ferromagnetic nanowires on s-wave superconductors, we propose to design Majorana bound states in artificially constructed single-atom chains with non-collinear spin-textures on elemental superconducting substrates using scanning tunnelling microscope (STM)-based atom manipulation techniques. We would like to study at the atomic level the formation of Shiba bands as a result of hybridization of individual Shiba impurity states as well as the emergence of zero-energy Majorana bound states as a function of chain structure, length, and composition. Moreover, we will construct model-type platforms, such as T-junctions, rings, and more complex network structures with atomic-scale precision as a basis for demonstrating the manipulation and braiding of Majorana bound states. We will make use of sophisticated experimental techniques, such as spin-resolved scanning tunnelling spectroscopy (STS) at micro-eV energy resolution, scanning Josephson tunnelling spectroscopy, and multi-probe STS under well-defined ultra-high vacuum conditions, in order to directly probe the nature of the magnetic state of the atomic wires, the spin-polarization of the emergent Majorana states, as well as the spatial nature of the superconducting order parameter in real space. Finally, we will try to directly probe the quantum exchange statistics of non-Abelian anyons in these atomically precise fabricated model-type systems.
Summary
Fault-tolerant topological quantum computation has become one of the most exciting research directions in modern condensed matter physics. As a key operation the braiding of non-Abelian anyons has been proposed theoretically. Such exotic quasiparticles can be realized as zero-energy Majorana bound states at the ends of one-dimensional magnetic nanowires in proximity to s-wave superconductors in the presence of high spin-orbit coupling. In contrast to previous attempts to realize such systems experimentally, based on the growth of semiconducting nanowires or the self-assembly of ferromagnetic nanowires on s-wave superconductors, we propose to design Majorana bound states in artificially constructed single-atom chains with non-collinear spin-textures on elemental superconducting substrates using scanning tunnelling microscope (STM)-based atom manipulation techniques. We would like to study at the atomic level the formation of Shiba bands as a result of hybridization of individual Shiba impurity states as well as the emergence of zero-energy Majorana bound states as a function of chain structure, length, and composition. Moreover, we will construct model-type platforms, such as T-junctions, rings, and more complex network structures with atomic-scale precision as a basis for demonstrating the manipulation and braiding of Majorana bound states. We will make use of sophisticated experimental techniques, such as spin-resolved scanning tunnelling spectroscopy (STS) at micro-eV energy resolution, scanning Josephson tunnelling spectroscopy, and multi-probe STS under well-defined ultra-high vacuum conditions, in order to directly probe the nature of the magnetic state of the atomic wires, the spin-polarization of the emergent Majorana states, as well as the spatial nature of the superconducting order parameter in real space. Finally, we will try to directly probe the quantum exchange statistics of non-Abelian anyons in these atomically precise fabricated model-type systems.
Max ERC Funding
2 499 750 €
Duration
Start date: 2019-01-01, End date: 2023-12-31
Project acronym ADSNeSP
Project Active and Driven Systems: Nonequilibrium Statistical Physics
Researcher (PI) Michael Elmhirst CATES
Host Institution (HI) THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE
Country United Kingdom
Call Details Advanced Grant (AdG), PE3, ERC-2016-ADG
Summary 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.
Summary
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.
Max ERC Funding
2 043 630 €
Duration
Start date: 2017-10-01, End date: 2022-09-30
Project acronym AGNES
Project ACTIVE AGEING – RESILIENCE AND EXTERNAL SUPPORT AS MODIFIERS OF THE DISABLEMENT OUTCOME
Researcher (PI) Taina Tuulikki RANTANEN
Host Institution (HI) JYVASKYLAN YLIOPISTO
Country Finland
Call Details Advanced Grant (AdG), SH3, ERC-2015-AdG
Summary The goals are 1. To develop a scale assessing the diversity of active ageing with four dimensions that are ability (what people can do), activity (what people do do), ambition (what are the valued activities that people want to do), and autonomy (how satisfied people are with the opportunity to do valued activities); 2. To examine health and physical and psychological functioning as the determinants and social and build environment, resilience and personal skills as modifiers of active ageing; 3. To develop a multicomponent sustainable intervention aiming to promote active ageing (methods: counselling, information technology, help from volunteers); 4. To test the feasibility and effectiveness on the intervention; and 5. To study cohort effects on the phenotypes on the pathway to active ageing.
“If You Can Measure It, You Can Change It.” Active ageing assessment needs conceptual progress, which I propose to do. A quantifiable scale will be developed that captures the diversity of active ageing stemming from the WHO definition of active ageing as the process of optimizing opportunities for health and participation in the society for all people in line with their needs, goals and capacities as they age. I will collect cross-sectional data (N=1000, ages 75, 80 and 85 years) and model the pathway to active ageing with state-of-the art statistical methods. By doing this I will create novel knowledge on preconditions for active ageing. The collected cohort data will be compared to a pre-existing cohort data that was collected 25 years ago to obtain knowledge about changes over time in functioning of older people. A randomized controlled trial (N=200) will be conducted to assess the effectiveness of the envisioned intervention promoting active ageing through participation. The project will regenerate ageing research by launching a novel scale, by training young scientists, by creating new concepts and theory development and by producing evidence for active ageing promotion
Summary
The goals are 1. To develop a scale assessing the diversity of active ageing with four dimensions that are ability (what people can do), activity (what people do do), ambition (what are the valued activities that people want to do), and autonomy (how satisfied people are with the opportunity to do valued activities); 2. To examine health and physical and psychological functioning as the determinants and social and build environment, resilience and personal skills as modifiers of active ageing; 3. To develop a multicomponent sustainable intervention aiming to promote active ageing (methods: counselling, information technology, help from volunteers); 4. To test the feasibility and effectiveness on the intervention; and 5. To study cohort effects on the phenotypes on the pathway to active ageing.
“If You Can Measure It, You Can Change It.” Active ageing assessment needs conceptual progress, which I propose to do. A quantifiable scale will be developed that captures the diversity of active ageing stemming from the WHO definition of active ageing as the process of optimizing opportunities for health and participation in the society for all people in line with their needs, goals and capacities as they age. I will collect cross-sectional data (N=1000, ages 75, 80 and 85 years) and model the pathway to active ageing with state-of-the art statistical methods. By doing this I will create novel knowledge on preconditions for active ageing. The collected cohort data will be compared to a pre-existing cohort data that was collected 25 years ago to obtain knowledge about changes over time in functioning of older people. A randomized controlled trial (N=200) will be conducted to assess the effectiveness of the envisioned intervention promoting active ageing through participation. The project will regenerate ageing research by launching a novel scale, by training young scientists, by creating new concepts and theory development and by producing evidence for active ageing promotion
Max ERC Funding
2 044 364 €
Duration
Start date: 2016-09-01, End date: 2021-08-31
