Xue Y.,Jilin University |
Matuszewski M.,Instytut Fizyki Polskiej Akademii Nauk
Physical Review Letters | Year: 2014
We predict the existence of a self-localized solution in a nonresonantly pumped exciton-polariton condensate. The solution has a shape resembling the well-known hyperbolic tangent profile of a dark soliton, but exhibits several distinct features. We find that it performs small oscillations, which are transformed into "soliton explosions" at lower pumping intensities. Moreover, after hundreds or thousands of picoseconds of apparently stable evolution the soliton decays abruptly, which is explained by the acceleration instability found previously in the Bekki-Nozaki hole solutions of the complex Ginzburg-Landau equation. We show that the soliton can be formed spontaneously from a small seed in the polariton field or by using spatial modulation of the pumping profile. © 2014 American Physical Society.
Matuszewski M.,Instytut Fizyki Polskiej Akademii Nauk
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010
We consider a spin-1 Bose-Einstein condensate trapped in a harmonic potential under the influence of a homogeneous magnetic field. We investigate spatial and spin structure of the mean-field ground states under constraints on the number of atoms and the total magnetization.We show that the trapping potential can make the antiferromagnetic condensate separate into three distinct phases and ferromagnetic condensate into two distinct phases. In the ferromagnetic case, the magnetization is located in the center of the harmonic trap, while in the antiferromagnetic case magnetized phases appear in the outer regions. We describe how the transition from the Thomas-Fermi regime to the single-mode approximation regime with decreasing number of atoms results in the disappearance of the domains. We suggest that the ground states can be created in experiment by adiabatically changing the magnetic-field strength. ©2010 The American Physical Society.
Agency: European Commission | Branch: FP7 | Program: MC-ITN | Phase: PEOPLE-2007-1-1-ITN | Award Amount: 3.21M | Year: 2008
We propose an Initial Training Network for advanced nanoscale semiconductor spintronics. This is a coordinated programme of technological, experimental and theoretical research, training and knowledge transfer, by a consortium of leading European academic and industrial research groups. Spintronics is becoming increasingly important as downscaling and power usage in microelectronics approaches fundamental limits. This ITN will provide a framework for structuring research and training efforts in this field and exploiting the new technology. The programme will move well beyond the worldwide state-of-the-art, through development of novel multifunctional nanospintronic devices, by transfer of device concepts to room temperature operation, and by exploration of the potential of low-dimensional systems. This coordinated wide-ranging and multidisciplinary programme is only achievable through a cross-European approach. The ITN will supply the required multidisciplinary and intersectorial training in materials development, device physics and technology and theory, which is crucial for ensuring a highly developed research infrastructure and a critical mass of qualified researchers in this key research area. Researcher mobility will be encouraged, with all appointed fellows spending periods at academic and industrial hosts. Industrial partners will be central to the training programme, ensuring that fellows have an understanding of the needs of end-users of the research. Transferable skills training will be supplied to meet wider employment market needs. The proposal is highly relevant to the ITN objectives, the Information Society Technologies and Nanotechnologies thematic areas of FP7, and ERA strategies to network centres of excellence, increase researcher mobility, and improve cohesion in research. The ITN will provide a body of highly skilled scientists, equipped with the expertise to ensure that European research continues to flourish in this vital area.
Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: REGPOT-2012-2013-1 | Award Amount: 5.53M | Year: 2013
The EAgLE project aims at establishing at the Institute of Physics, Polish Academy of Sciences (IFPAN) a leading multiprofile research Centre for designing and fabricating new materials, their characterization and testing under extreme experimental conditions. The Centre will identify and select novel materials, structures, phenomena, and computational protocols for functional new-concept nanodevices. The Centre will benefit from twinning with 16 partnering institutions having the sound expertise in the field of materials fabrication (e.g. MBE, chemical synthesis, lithography, FIB), characterization (e.g. XPS, TEM, EELS, synchrotron diffraction and spectroscopy, NMR), nanodevice design and testing (e.g. semi- and superconducting electronics, cryogenics, computer simulations). The research potential will be enhanced through employment of both experienced and young researchers in the relevant fields. Within the project an X-Ray Photoelectron Spectrometer (XPS) will be acquired, making it possible to perform element specific and chemical sensitive characterization of materials with 3D resolution. A cryogen-free dilution refrigerator will be another essential purchase opening new opportunities to follow properties of the materials and devices down to a few miliKelvins. An important goal of the Centre will be exploration and standardization of user-friendly computational methods for materials design and for modelling of functional properties and nanodevices, including code validation and benchmarking, available also to external users. The awareness of issues related to the field of intellectual property, licensing, and patenting will be raised among the staff members via a series of dedicated workshops, in order to improve the transfer of innovations to new spin-offs, SMEs, and industry.
Agency: European Commission | Branch: FP7 | Program: ERC-AG | Phase: ERC-AG-PE3 | Award Amount: 2.44M | Year: 2009
Low-temperature studies of transition metal doped III-V and II-VI compounds carried out over the last decade have demonstrated the unprecedented opportunity offered by these systems for exploring physical phenomena and device concepts in previously unavailable combinations of quantum structures and ferromagnetism in semiconductors. The work proposed here aims at combining and at advancing epitaxial methods, spatially-resolved nano-characterisation tools, and theoretical modelling in order to understand the intricate interplay between carrier localisation, magnetism, and magnetic ion distribution in DMS, and to develop functional DMS structures. To accomplish these goals we will take advantage of two recent breakthroughs in materials engineering. First, the attainment of high-k oxides makes now possible to generate interfacial hole densities up to 10^21 cm-3. We will exploit gated thin layers of DMS phosphides, nitrides, and oxides, in which hole delocalization and thus high temperature ferromagnetism is to be expected under gate bias. Furthermore we will systematically investigate how the Curie temperature of (Ga,Mn)As can be risen above 180 K. Second, the progress in nanoscale chemical analysis has allowed demonstrating that high temperature ferromagnetism of semiconductors results from nanoscale crystallographic or chemical phase separations into regions containing a large concentration of the magnetic constituent. We will elaborate experimentally and theoretically epitaxy and co-doping protocols for controlling the self-organised growth of magnetic nanostructures, utilizing broadly synchrotron radiation and nanoscopic characterisation tools. The established methods will allow us to obtain on demand either magnetic nano-dots or magnetic nano-columns embedded in a semiconductor host, for which we predict, and will demonstrate, ground-breaking functionalities. We will also assess reports on the possibility of high-temperature ferromagnetism without magnetic ions.
Agency: European Commission | Branch: FP7 | Program: MC-ERG | Phase: FP7-PEOPLE-2009-RG | Award Amount: 45.00K | Year: 2010
The quantum dynamics of several characteristic simple situations in the dynamics of ultracold Bose gases will be systematically studied for a broad range of their basic parameters, with particular emphasis on the incoherent particles and the possibility of their stimulated growth into coherent phase grains. Situations include supersonic flow past an obstacle, collisions of BECs, reflection of a BEC from a barrier, and interaction of obstacles and vortices. The aim is to produce quantitative maps of their behaviour as a function of basic scaled parameters such as velocity, obstacle dimensions, and duration. To date, knowledge of these simple dynamical situations is mostly limited to isolated parameter choices, whereas this project objective is to make the coverage broad, comprehensive and continuous. This has many practical applications to understanding of more complex/realistic situations that can be broken up into the simpler elements, and is timely given the increase in BEC dynamics experiments in the last 2-3 years. Simulations with phase-space methods of the first-principles, c-field, and Bogoliubov variety are essential for broad coverage. This matches and will build on the existing extensive and deep experience of the researcher in developing and using such methods, obtained during the EIF fellowship. Finalisation of the stochastic time-adaptive Bogoliubov simulation method roughly developed then is necessary and planned. 3 years of research at the Polish Academy of Sciences in Warsaw is planned. It is already home to several world experts on Bose gas dynamics, and several other expert groups are in Warsaw and Poland, so professional integration will be thorough, and EU-wide scientific integration will increase. The project work will be used to obtain a habilitation, necessary to obtain a permanent independent research position in the Polish system.
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: NMP-2007-1.1-2 | Award Amount: 5.00M | Year: 2008
Recent developments in the design and synthesis of nanoscale building blocks as active elements in opto- or bio-electronic devices with tailored electronic functionality have the potential to open up new horizons in nanoscience and also revolutionise multi-billion dollar markets across multiple technology sectors including healthcare, printable electronics, and security. Ligand-stabilised inorganic nanocrystals (~2-30 nm core diameters) and functional organic molecules are attractive building blocks due to their size dependent opto-electronic properties, the availability of low-cost synthesis processes and the potential for formation of ordered structures via (bio) molecular recognition and self-assembly. Harnessing the complementary properties of both nanocrystals and functional molecules thus represents a unique opportunity for generation of new knowledge and development of new classes of high knowledge-content materials with specific functionality tailored for key applications, e.g., printable electronics, biosensing or energy conversion in the medium term, and radically new information and signal processing paradigms in the long term. Self-assembly and self-organisation processes offer the potential to achieve dimensional control of novel multifunctional materials at length scales not accessible to conventional top-down technologies based on lithography. It is critical for European industry to develop new knowledge and low-cost, scaleable processes for assembly and electrical interfacing of these multifunctional materials with conventional contact electrodes in order to produce into tailored devices and products, in particular on low-cost substrates. The FUNMOL consortium will deliver substantial innovation to European industry via development of cost-effective, scaleable processes for directed assembly of high-knowledge content nanocrystal-molecule materials into electrically-interfaced devices at silicon oxide, glass and plastic substrates.
Agency: European Commission | Branch: FP7 | Program: MC-IRSES | Phase: FP7-PEOPLE-2012-IRSES | Award Amount: 428.40K | Year: 2013
BRASINOEU aims to study the translocation and nanosafety issues of engineered metal oxide nanoparticles (NPs).The new scientific and technology developments of nanotechnology require a deeper knowledge of the effects of nanotechnology based products on human health. This knowledge is fundamental for the development of nanotechnology and to achieve its full acceptance. The concept of safe by design is based on the application of nanosafety to design the nanomaterials in order to prevent or reduce their possible harm to humans and the environment. The project encompass the synthesis of metal oxide NPs, with a focus on magnetic oxides, their surface modification and post modification in biological fluids; immunological and genotoxicity studies, and translocation studies both in vitro and in vivo. The project will seek to establish relationships between designed NP properties and their translocation at cellular and body level as well as their immune- and genotoxic response. This is a fundamental issue for the safe design of NPs. Also, the toxicological response will be studied as a function of the uptake dose of NPs. At cellular level a battery of techniques will be applied for localization and quantification of NPs: Transmission Electron Microscopy, Raman, Confocal Microscopy, Ion Beam Microscopy, etc. Positron Emission Tomography and Magnetic Resonance Imaging will be employed for biodistribution and quantification studies in animal models. BRASINOU is formed by an international team with the required and complementary expertise to address the proposed work from an international and multidisciplinary perspective. The project gathers internationally recognized groups in immunology, genotoxicity, nanoparticle synthesis, surface chemistry, biophysics, imaging and materials science. The complementary of the groups involved in the project will help to develop new highly skilled professional and scientific horizontal connections.
Agency: European Commission | Branch: FP7 | Program: MC-ITN | Phase: PEOPLE-2007-1-1-ITN | Award Amount: 4.78M | Year: 2008
Indium nitride is a new narrow gap semiconductor (<0.7 eV), which alloys with GaN (3.5 eV) and AlN (6.2 eV) will allow the spectral range from telecom to hard UV wavelengths to be covered. This narrow band gap makes InN an exciting material from which to develop highest efficiency solar cells. Moreover, due to an electron mobility of around 4000 cm2/Vs and very high saturation velocities, InN is an ideal material for the development of high electron mobility devices capable of operating in the Terahertz range. To ensure the production of reliable commercial devices, rigorous fundamental research is required to understand the layer growth mechanisms and optimize material properties. In RAINBOW, academic and industrial consortium, the theoretical work will encompass modelling of the atomic structure and properties of the material from empirical potentials to ab initio techniques. Experiments will provide correlated structural, electronic, optical and chemical information from the nano to the macroscopic scale. In a closely concerted effort, we will determine the best conditions for the growth of highest quality InN and In rich (In,Ga,Al)N alloys by the main growth techniques (MOVPE, PAMBE,HVPE ). Under the supervision of world leading experts, numerous young researchers will directly benefit from this interdisciplinary and multisectorial research and training effort. The young researchers involved in this programme will also learn to manage research and industrial projects.
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: NMP.2013.1.1-2 | Award Amount: 5.28M | Year: 2013
The major bottleneck for plant biomass processing is fiber saccharification: the conversion of cell wall lignocellulosic biomass into fermentable sugars (en route to production of value-added chemicals like second generation biofuels). Some microbes enhance this step by using natural self-assembling proteinaceous nanocatalists known as cellulosomes. CellulosomePlus targets rational design of optimized cellulosomes to overcome this problem.This would allow efficient production of biofuels from low-value raw materials like inedible parts of plants and industrial residues (which are all renewable, sustainable and inexpensive). First we propose to characterize the physicochemical and structural properties (including mechanostability) as well as interactions of enzymes and scaffolds from natural cellulosomes and non-cellulosomal components. In parallel, we will characterize a suitable residual substrate from municipal waste (organic fraction of municipal solid waste) and develop improved assays to reliably follow cellulosomal enzymatic activity. The acquired knowledge will be complemented with rapid computational modelling at the atomic and supramolecular levels for testing and predictions. Experimental and theoretical knowledge will be then integrated to design improved cellulosomes (with high-selectivity, activity and cost-effectiveness). Further improvement will be obtained by iteration using high throughput screening of components. The improved cellulosomes generated through this innovative multidisciplinary approach represent a step towards green chemistry since they are biodegradable proteinaceous materials and therefore by-products and/or wastes are minimized due to the high enzymatic selectivity. Finally, the production of the optimized cellulosomes (and the process involved) will be scaled up to preindustrial scale to demonstrate their viable commercial production. These results will be patented and a roadmap will be drawn up towards future standardization.