ERC FUNDED PROJECTS

Correlated electrons are at the forefront of condensed matter theory. Interacting quasi-1D electrons have seen vast progress in analytical and numerical theory, and thus in fundamental understanding and quantitative prediction. Yet, in the 1D limit fluctuations preclude important technological use, particularly of superconductors. In contrast, high-Tc superconductors in 2D/3D are not precluded by fluctuations, but lack a fundamental theory, making prediction and engineering of their properties, a major goal in physics, very difficult. This project aims to combine the advantages of both areas by making major progress in the theory of quasi-1D electrons coupled to an electron bath, in part building on recent breakthroughs (with the PIs extensive involvement) in simulating 1D and 2D electrons with parallelized density matrix renormalization group (pDMRG) numerics. Such theory will fundamentally advance the study of open electron systems, and show how to use 1D materials as elements of new superconducting (SC) devices and materials: 1) It will enable a new state of matter, 1D electrons with true SC order. Fluctuations from the electronic liquid, such as graphene, could also enable nanoscale wires to appear SC at high temperatures. 2) A new approach for the deliberate engineering of a high-Tc superconductor. In 1D, how electrons pair by repulsive interactions is understood and can be predicted. Stabilization by reservoir - formed by a parallel array of many such 1D systems - offers a superconductor for which all factors setting Tc are known and can be optimized. 3) Many existing superconductors with repulsive electron pairing, all presently not understood, can be cast as 1D electrons coupled to a bath. Developing chain-DMFT theory based on pDMRG will allow these materials SC properties to be simulated and understood for the first time. 4) The insights gained will be translated to 2D superconductors to study how they could be enhanced by contact with electronic liquids.

1 491 013 €

Start date: 2018-10-01, End date: 2024-03-31

CO2 reduction reaction (CO2RR) holds great promise for conversion of the green-house gas carbon dioxide into chemical fuels. The absence of catalytic materials demonstrating high performance and high selectivity currently hampers practical demonstration. CO2RR is also limited by the low solubility of CO2 in the electrolyte solution and therefore electrocatalytic reactions in gas phase using gas diffusion electrodes would be preferred. 2D materials have recently emerged as a novel class of electrocatalytic materials thanks to their rich structures and electronic properties. The synthesis of novel 2D catalysts and their implementation into photocatalytic systems would be a major step towards the development of devices for storing solar energy in the form of chemical fuels. With 2D-4-CO2, I propose to: 1) develop novel class of CO2RR catalysts based on conducting 2D nanosheets and 2) demonstrate photocatalytic conversion of CO2 into chemical fuels using structure engineered gas diffusion electrodes made of 2D conducting catalysts. To reach this goal, the first objective of 2D-4-CO2 is to provide guidelines for the development of novel cutting-edge 2D catalysts towards CO2 conversion into chemical fuel. This will be possible by using a multidisciplinary approach based on 2D materials engineering, advanced methods of characterization and novel designs of gas diffusion electrodes for the reduction of CO2 in gas phase. The second objective is to develop practical photocatalytic systems using van der Waals (vdW) heterostructures for the efficient conversion of CO2 into chemical fuels. vdW heterostructures will consist in rational designs of 2D materials and 2D-like materials deposited by atomic layer deposition in order to achieve highly efficient light conversion and prolonged stability. This project will not only enable a deeper understanding of the CO2RR but it will also provide practical strategies for large-scale application of CO2RR for solar fuel production.

1 499 931 €

Start date: 2019-01-01, End date: 2023-12-31

Climate change and the decreasing availability of fossil fuels require society to move towards sustainable and renewable resources. 2DNanoCaps will focus on electrochemical energy storage, specifically supercapacitors. In terms of performance supercapacitors fill up the gap between batteries and the classical capacitors. Whereas batteries possess a high energy density but low power density, supercapacitors possess high power density but low energy density. Efforts are currently dedicated to move supercapacitors towards high energy density and high power density performance. Improvements have been achieved in the last few years due to the use of new electrode nanomaterials and the design of new hybrid faradic/capacitive systems. We recognize, however, that we are reaching a newer limit beyond which we will only see small incremental improvements. The main reason for this being the intrinsic difficulty in handling and processing materials at the nano-scale and the lack of communication across different scientific disciplines. I plan to use a multidisciplinary approach, where novel nanomaterials, existing knowledge on nano-scale processing and established expertise in device fabrication and testing will be brought together to focus on creating more efficient supercapacitor technologies. 2DNanoCaps will exploit liquid phase exfoliated two-dimensional nanomaterials such as transition metal oxides, layered metal chalcogenides and graphene as electrode materials. Electrodes will be ultra-thin (capacitance and thickness of the electrodes are inversely proportional), conductive, with high dielectric constants. Intercalation of ions between the assembled 2D flakes will be also achievable, providing pseudo-capacitance. The research here proposed will be initially based on fundamental laboratory studies, recognising that this holds the key to achieving step-change in supercapacitors, but also includes scaling-up and hybridisation as final objectives.

1 501 296 €

Start date: 2011-10-01, End date: 2016-09-30

Quantum optics, the study of how discrete packets of light (photons) and matter interact, has led to the development of remarkable new technologies which exploit the bizarre properties of quantum mechanics. These quantum technologies are primed to revolutionize the fields of communication, information processing, and metrology in the coming years. Similar to contemporary technologies, the future quantum machinery will likely consist of a semiconductor platform to create and process the quantum information. However, to date the demanding requirements on a quantum photonic platform have yet to be satisfied with conventional bulk (three-dimensional) semiconductors. To surmount these well-known obstacles, a new paradigm in quantum photonics is required. Initiated by the recent discovery of single photon emitters in atomically flat (two-dimensional) semiconducting materials, 2DQP aims to be at the nucleus of a new approach by realizing quantum optics with ultra-stable (coherent) quantum states integrated into devices with electronic and photonic functionality. We will characterize, identify, engineer, and coherently manipulate localized quantum states in this two-dimensional quantum photonic platform. A vital component of 2DQP’s vision is to go beyond the fundamental science and achieve the ideal solid-state single photon device yielding perfect extraction - 100% efficiency - of on-demand indistinguishable single photons. Finally, we will exploit this ideal device to implement the critical building block for a photonic quantum computer.

1 999 135 €

Start date: 2018-01-01, End date: 2022-12-31