ERC FUNDED PROJECTS

Peptide building blocks serve as very attractive bio-inspired elements in nanotechnology owing to their controlled self-assembly, inherent biocompatibility, chemical versatility, biological recognition abilities and facile synthesis. We have demonstrated the ability of remarkably simple aromatic peptides to form well-ordered nanostructures of exceptional physical properties. By taking inspiration from the minimal recognition modules used by nature to mediate coordinated processes of self-assembly, we have developed building blocks that form well-ordered nanostructures. The compact design of the building blocks, and therefore, the unique structural organization, resulted in metallic-like Young's modulus, blue luminescence due to quantum confinement, and notable piezoelectric properties. The goal of this proposal is to develop two new fronts for bio-inspired building block repertoire along with co-assembly to provide new avenues for organic nanotechnology. This will combine our vast experience in the assembly of aromatic peptides together with additional structural modules from nature. The new entities will be developed by exploiting the design principles of small aromatic building blocks to arrive at the smallest possible module that form super helical assembly based on the coiled coil motifs and establishing peptide nucleic acids based systems to combine the worlds of peptide and DNA nanotechnologies. The proposed research will combine extensive design and synthesis effort to provide a very diverse collection of novel buildings blocks and determination of their self-assembly process, followed by broad chemical, physical, and biological characterization of the nanostructures. Furthermore, effort will be made to establish supramolecular co-polymer systems to extend the morphological control of the assembly process. The result of the project will be a large and defined collection of novel chemical entities that will help reshape the field of bioorganic nanotechnology.

3 003 125 €

Start date: 2016-06-01, End date: 2021-05-31

The discovery of the fractional quantum Hall effect created a revolution in solid state research by introducing a new state of matter resulting from strong electron interactions. The new state is characterized by excitations (quasi-particles) that carry fractional charge, which are expected to obey fractional statistics. While odd denominator fractional states are expected to have an abelian statistics, the newly discovered 5/2 even denominator fractional state is expected to have a non-abelian statistics. Moreover, a large number of emerging proposals predict that the latter state can be employed for topological quantum computing ( Station Q was founded by Microsoft Corp. in order to pursue this goal). This proposal aims at studying the abelian and non-abelian fractional charges, and in particular to observe their peculiar statistics. While charges are preferably determined by measuring quantum shot noise, their statistics must be determined via interference experiments, where one particle goes around another. The experiments are very demanding since the even denominator fractions turn to be very fragile and thus can be observed only in the purest possible two dimensional electron gas and at the lowest temperatures. While until very recently such high quality samples were available only by a single grower (in the USA), we have the capability now to grow extremely pure samples with profound even denominator states. As will be detailed in the proposal, we have all the necessary tools to study charge and statistics of these fascinating excitations, due to our experience in crystal growth, shot noise and interferometry measurements.

2 000 000 €

Start date: 2009-01-01, End date: 2013-12-31

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.

2 440 000 €

Start date: 2009-01-01, End date: 2013-12-31

We present a novel constructive approach for realizations of topological states of matter. Our approach starts with well-understood building blocks, and proceeds towards coupling them to create the desired states. This approach promises both a guide for a tunable experimental realization of states which have not been observed so far, and a theoretical tool for deeper understanding of different topological states, their dualities and inter-relations. We will apply the constructive approach in two different directions. In the first direction our goal will be the construction of topological superconductors. Our tool will be Josephson junctions in which superconductors are coupled by two- and three-dimensional electronic non-superconducting systems. Two dimensional examples include transition metal dichalcogenides, Quantum Hall states, Quantum Anomalous Hall states, and the (111) bi-layer state, which may be viewed as a fractionalized electron-hole condensate. Three dimensional examples include Weyl semi-metals and weak topological insulators. In the second direction our goal is the construction of fractionalized spin liquid states. Our building block will be a Majorana-Cooper box, which is a superconducting quantum dot coupled to semi-conducting wires that host Majorana zero modes. We will consider arrays of such boxes. The ratio of the box's charging energy to inter-box tunnel-coupling determines whether the array is superconducting or insulating. We will aim to use insulating arrays for realizing fractionalized and non-abelian spin liquids, study the transition to the superconducting state, and search for possible relations between the topological properties on both sides of the transition. A deeper comprehension and a feasible path for realization of these states would have a profound effect on the field of topological matter and will open novel avenues for universal topological quantum computers.

1 532 163 €

Start date: 2018-10-01, End date: 2023-09-30