Project

The goal of the project is to develop multi-scale models of complex materials or molecular systems in which dynamical many-particle correlations play a significant role. The dynamics will be followed over a multitude of length scales, from the sub-atomic scales of strongly correlated electronic systems through the atomistic modelling of semiconductor devices and interfaces up to the mesoscale models of protein and nanocrystal aggregation.

The specific subject areas of the project are the following:

Theme 1 (supervised by prof. Krzysztof Byczuk and prof. Jacek A. Majewski)
Correlation induced phenomena in electronic models with predictive power. (Tasks 1-5)

Within this theme we plan to combine the DMFT and the density functional a approach to model correlated electron systems in presence of interfaces, boundaries, and disorder.

Task 1 (01/07/11-30/11/12): Impurity solvers. The continuous time quantum Monte Carlo algorithms (CT-QMC) will be used to simulate a single and multi-orbital impurity or a cluster of lattice sites embedded in a fermionic baths within the DMFT self-consistency conditions. The CT-QMC, based on stochastic sampling of Feynman diagrams within infinite order perturbation expansion, is currently the most efficient and flexible simulation method of solving the DMFT equations.

Task 2 (01/12/12-30/05/14): R-DMFT for interfaces. The CT-QMC solvers wil lbe used to model inhomogeneous systems within real-space DMFT, investigate role of local impurity randomness, external smooth potential, abrupt change in lattice structure (interface, quantum wells, hetrostructures).

Task 3 (01/12/12-30/05/14): Real correlated electrons with interfaces. We will use CT-QMC solver with the DFT-type ab initio input to analyze interactions and hopping Hamiltonians in systems with inhomogeneities for realistic modeling of systems with interfaces. Different phase instabilities will be investigated in different type of oxides. We hope to find a useful rules governing appearance of new phases which might be of crucial interest for practical searching of new functional materials.

Task 4 (01/06/14-30/06/15): Correlation in magnetic semiconductors. The CT-QMC with the DFT-type ab initio input will be used in modeling of magnetic semiconductors. Particular attention will be paid to the role o clustering of magnetic ions in the semiconducting host and its role in formation of various forms of magnetism.

Task 5 (01/06/14-30/06/15): Correlation effects in topological insulators. We will use the CT-QMC solver and the DFT-type ab initio input to investigate topological insulators and their boundaries. The role of electron correlation on topological properties, i.e. surface metallicity, will be investigated in detail.

Theme 2 (supervised by dr hab. Piotr Szymczak)
The role of hydrodynamic correlations during self-assembly processes at the nanoscale. (Tasks 6-7)

Within this theme we plan to study self-organization and self-assembly in fluidic environment, with a special focus on a influence of hydrodynamic interactions and flow effects on the emerging structure and its properties.

Task 6 (part I 01/07/11-30/05/13; part II 01/06/13-30/06/15): The dynamics of protein fibril formation. As elucidated by recent experimental studies (see e.g. Loksztejn and Dzwolak, J. Mol. Biol. 395, 643 2010, and references therein) hydrodynamic correlations may play a highly nontrivial role in the protein aggregation process. In particular, they influence the macroscopic properties of aggregates, including their chirality. However, a theoretical model of that process is still missing, mostly because of the number of different physical mechanisms and a wide range of lengthscales involved: from the interactions between individual aminoacids of the proteins, which have to be resolved at a atomic level to the collective motions of tens or hundreds of protein chains as they aggregate, for which a computationally effective and yet realistic coarse-grained model must be constructed. Our goal will be to construct such a multi-scale model and then use it to understand the details of the fibril formation processes.

Task 7 (part I 01/07/11-30/05/12; part II 01/06/12-30/05/13; part III 01/06/13-30/06/15): Charge-transport properties of nano-aggregates. In the production of conductive nanolayers, an attractive alternatives to the top-down methods (such as physical vapour deposition or photolitography) are "wet" bottom-up-approaches making use of self-assembly of nanoparticles in the liquid enviroment, with subsequent evaporation of the solvent. The structures of the resulting aggregates depend both on the details of the interparticle potential and on the dynamics of the aggregation itself – they range from the regular close-packed arrays and nano-networks with well organized cells to multi-cellular fractal structures and glassy disordered deposits. The fabrication methods and the practical applications of various nanomaterials are fast advancing, mainly using the accumulated empirical knowledge; however, theoretical understanding of this process – necessary for its effective application – is still missing. The goal of the present Task will be to construct a computational model of this phenomenon by simulating the aggregation and evaporation processes and then calculating the effective properties of the resulting structures in order to assess the optimum conditions that produce nanoparticle films of desired properties.