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 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 ANYONIC
Project Statistics of Exotic Fractional Hall States
Researcher (PI) Mordehai HEIBLUM
Host Institution (HI) WEIZMANN INSTITUTE OF SCIENCE
Country Israel
Call Details Advanced Grant (AdG), PE3, ERC-2018-ADG
Summary Since their discovery, Quantum Hall Effects have unfolded intriguing avenues of research, exhibiting a multitude of unexpected exotic states: accurate quantized conductance states; particle-like and hole-conjugate fractional states; counter-propagating charge and neutral edge modes; and fractionally charged quasiparticles - abelian and (predicted) non-abelian. Since the sought-after anyonic statistics of fractional states is yet to be verified, I propose to launch a thorough search for it employing new means. I believe that our studies will serve the expanding field of the emerging family of topological materials.
Our on-going attempts to observe quasiparticles (qp’s) interference, in order to uncover their exchange statistics (under ERC), taught us that spontaneous, non-topological, ‘neutral edge modes’ are the main culprit responsible for qp’s dephasing. In an effort to quench the neutral modes, we plan to develop a new class of micro-size interferometers, based on synthetically engineered fractional modes. Flowing away from the fixed physical edge, their local environment can be controlled, making it less hospitable for the neutral modes.
Having at hand our synthetized helical-type fractional modes, it is highly tempting to employ them to form localize para-fermions, which will extend the family of exotic states. This can be done by proximitizing them to a superconductor, or gapping them via inter-mode coupling.
The less familiar thermal conductance measurements, which we recently developed (under ERC), will be applied throughout our work to identify ‘topological orders’ of exotic states; namely, distinguishing between abelian and non-abelian fractional states.
The proposal is based on an intensive and continuous MBE effort, aimed at developing extremely high purity, GaAs based, structures. Among them, structures that support our new synthetic modes that are amenable to manipulation, and others that host rare exotic states, such as v=5/2, 12/5, 19/8, and 35/16.
Summary
Since their discovery, Quantum Hall Effects have unfolded intriguing avenues of research, exhibiting a multitude of unexpected exotic states: accurate quantized conductance states; particle-like and hole-conjugate fractional states; counter-propagating charge and neutral edge modes; and fractionally charged quasiparticles - abelian and (predicted) non-abelian. Since the sought-after anyonic statistics of fractional states is yet to be verified, I propose to launch a thorough search for it employing new means. I believe that our studies will serve the expanding field of the emerging family of topological materials.
Our on-going attempts to observe quasiparticles (qp’s) interference, in order to uncover their exchange statistics (under ERC), taught us that spontaneous, non-topological, ‘neutral edge modes’ are the main culprit responsible for qp’s dephasing. In an effort to quench the neutral modes, we plan to develop a new class of micro-size interferometers, based on synthetically engineered fractional modes. Flowing away from the fixed physical edge, their local environment can be controlled, making it less hospitable for the neutral modes.
Having at hand our synthetized helical-type fractional modes, it is highly tempting to employ them to form localize para-fermions, which will extend the family of exotic states. This can be done by proximitizing them to a superconductor, or gapping them via inter-mode coupling.
The less familiar thermal conductance measurements, which we recently developed (under ERC), will be applied throughout our work to identify ‘topological orders’ of exotic states; namely, distinguishing between abelian and non-abelian fractional states.
The proposal is based on an intensive and continuous MBE effort, aimed at developing extremely high purity, GaAs based, structures. Among them, structures that support our new synthetic modes that are amenable to manipulation, and others that host rare exotic states, such as v=5/2, 12/5, 19/8, and 35/16.
Max ERC Funding
1 801 094 €
Duration
Start date: 2019-05-01, End date: 2024-10-31
Project acronym ARTIMATTER
Project "Lego-Style Materials, Structures and Devices Assembled on Demand from Isolated Atomic Planes"
Researcher (PI) Andre Geim
Host Institution (HI) THE UNIVERSITY OF MANCHESTER
Country United Kingdom
Call Details Advanced Grant (AdG), PE3, ERC-2012-ADG_20120216
Summary "Following the advent of graphene with its wide range of unique properties, several other one-atom-thick crystals have been isolated and their preliminary studies have been undertaken. They range from semiconducting monolayers of MoS2 and NbSe2, which similar to graphene exhibit the electric field effect and relatively high electronic quality, to wide-gap insulators such as boron-nitride monolayers that can serve as atomically-thin tunnel barriers.
This library of two-dimensional crystals opens a possibility to construct various 3D structures with on-demand properties, which do not exist in nature but can be assembled in Lego style by stacking individual atomic planes on top of each other in a desired sequence. This project is to explore this new avenue.
We will design, fabricate and study multilayer materials ranging from basic heterostructures that consist of a few alternating layers of graphene and boron nitride and already exhibit a rich spectrum of new phenomena, as recently demonstrated by the applicant’s group, to complex artificial materials containing many layers of different 2D crystals and mimicking, for example, layered superconductors. In a similar manner, various electronic, optoelectronic, micromechanical and other devices will be developed and investigated. The applicant’s aim is to search for new materials with unique properties, novel devices with better characteristics and new physics that is likely to emerge along the way.
The proposed research offers many exciting opportunities and can lead to the development of a large unexplored field with impact exceeding even that of graphene research. This presents a unique, once-in-decade, opportunity to make a very significant breakthrough in condensed matter physics and materials science."
Summary
"Following the advent of graphene with its wide range of unique properties, several other one-atom-thick crystals have been isolated and their preliminary studies have been undertaken. They range from semiconducting monolayers of MoS2 and NbSe2, which similar to graphene exhibit the electric field effect and relatively high electronic quality, to wide-gap insulators such as boron-nitride monolayers that can serve as atomically-thin tunnel barriers.
This library of two-dimensional crystals opens a possibility to construct various 3D structures with on-demand properties, which do not exist in nature but can be assembled in Lego style by stacking individual atomic planes on top of each other in a desired sequence. This project is to explore this new avenue.
We will design, fabricate and study multilayer materials ranging from basic heterostructures that consist of a few alternating layers of graphene and boron nitride and already exhibit a rich spectrum of new phenomena, as recently demonstrated by the applicant’s group, to complex artificial materials containing many layers of different 2D crystals and mimicking, for example, layered superconductors. In a similar manner, various electronic, optoelectronic, micromechanical and other devices will be developed and investigated. The applicant’s aim is to search for new materials with unique properties, novel devices with better characteristics and new physics that is likely to emerge along the way.
The proposed research offers many exciting opportunities and can lead to the development of a large unexplored field with impact exceeding even that of graphene research. This presents a unique, once-in-decade, opportunity to make a very significant breakthrough in condensed matter physics and materials science."
Max ERC Funding
2 200 000 €
Duration
Start date: 2013-05-01, End date: 2018-04-30
Project acronym ASCIR
Project Active Suspensions with Controlled Interaction Rules
Researcher (PI) Clemens Bechinger
Host Institution (HI) UNIVERSITAT KONSTANZ
Country Germany
Call Details Advanced Grant (AdG), PE3, ERC-2015-AdG
Summary Self-propelling, i.e., active colloidal particles constitute a novel class of non-equilibrium systems which exhibit structural and dynamical features similar to those in assemblies of bacteria or other motile organisms. Due to their reduced complexity, they provide an intriguing chance to understand the formation of dynamical structures in non-equilibrium systems in unprecedented detail. A central question in this rapidly growing field is, how interaction-rules determine the creation of e.g. swarms or complex networks. In addition to ordinary inter particle and hydrodynamic forces, interaction-rules can be much more complex. For example, they can regulate the particle motility depending on their relative orientation, their local density or otherwise distinct particle configurations.
Here, we propose an experimental approach which aims towards controlling the amplitude and direction of the particle’s motility in dense active suspensions on a single particle level. Particle-propulsion is achieved by a light-activated diffusiophoretic mechanism, where the particle motility is controlled by an incident light field. By means of an acoustic-optical modulator and a feed-back loop, we create dynamical and spatially-resolved light fields which depend on the current configuration of active particles and user-defined interaction rules. Because these rules are imposed externally and not by internal forces, this permits the experimental realization of a wide range of rules (linear, non-linear, and even non-reciprocal) in dense, two-dimensional active systems. We expect, that the experimental realization of user-defined interaction-rules largely extends our understanding how active matter can organize in dynamical structures. In addition, the perspective of enhanced control of active particles, as suggested within this proposal, will be of considerable importance for their use as autonomous micro robots which will deliver payloads in liquid environments.
Summary
Self-propelling, i.e., active colloidal particles constitute a novel class of non-equilibrium systems which exhibit structural and dynamical features similar to those in assemblies of bacteria or other motile organisms. Due to their reduced complexity, they provide an intriguing chance to understand the formation of dynamical structures in non-equilibrium systems in unprecedented detail. A central question in this rapidly growing field is, how interaction-rules determine the creation of e.g. swarms or complex networks. In addition to ordinary inter particle and hydrodynamic forces, interaction-rules can be much more complex. For example, they can regulate the particle motility depending on their relative orientation, their local density or otherwise distinct particle configurations.
Here, we propose an experimental approach which aims towards controlling the amplitude and direction of the particle’s motility in dense active suspensions on a single particle level. Particle-propulsion is achieved by a light-activated diffusiophoretic mechanism, where the particle motility is controlled by an incident light field. By means of an acoustic-optical modulator and a feed-back loop, we create dynamical and spatially-resolved light fields which depend on the current configuration of active particles and user-defined interaction rules. Because these rules are imposed externally and not by internal forces, this permits the experimental realization of a wide range of rules (linear, non-linear, and even non-reciprocal) in dense, two-dimensional active systems. We expect, that the experimental realization of user-defined interaction-rules largely extends our understanding how active matter can organize in dynamical structures. In addition, the perspective of enhanced control of active particles, as suggested within this proposal, will be of considerable importance for their use as autonomous micro robots which will deliver payloads in liquid environments.
Max ERC Funding
2 036 750 €
Duration
Start date: 2016-10-01, End date: 2021-09-30
