Fyzikální ústav Akademie věd ČR

Institute and media

Quarks, Black Holes, CERN & its surroundings

CERN Document Server, 18.5.2011.

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Participants Forum and Fellows Meeting

HiPER News, 3.6.2010.

Members of the HiPER community gathered...

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Czech Institute of Physics boosts efficiency

IBM Cases studies, 5.3.2010.

IBM iDataPlex has a really...

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What Makes It So Hard?

Physical Review Focus, 4/9/ 2009.

A recently developed material...

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Research subjects at department 23

Interdisciplinary physics

Applications of theoretical physics in other branches of science are investigated. Special attention is paid on complex networks both in social systems and in biology. Empirical data are analyzed by methods of random matrix theory, where spectra of the matrices and localization properties visualise relevant structural features. This way we for example reveal strongly interacting clusters of agents in electronic commerce or functional units of metabolic networks in living organisms.  The full text >>

Statistical physics of random systems and nonequilibrium thermodynamics

Theory of random systems, in particular spin glasses, is pursued. Microscopic approaches bases on the real-replica method combined with TAP equations are used to understand the mean-field theory of spin glasses.
In nonequilibrium systems dynamical fluctuations in irreversible processes, variational formulation of nonequilibrium steady states and nonequilibrium thermodynamics beyond linear response are investigated.   The full text >>

Surface nanostructure

Structural properties and mechanism of formation of surface nanostructure of metals, semiconductors, and multi-component materials are studied by numerical simulations. Molecular dynamics and Monte-Carlo simulations are combined to achieve a multiscale description of the critical behavior of relevant statistical mechanical quantities.  The full text >>

Transient Dynamics of Electrons in the Mesoscopic Systems and in the Bulk

This research area concerns the electron response to sudden/fast changes of boundary conditions, like coupling to the particle reservoirs (leads) and to the environment (thermal baths), or to the excitation by short external pulses of light or other fields. The research aims at an adequate description of the non-equilibrium correlated state during the initial transient, the decay of correlations as a gate to the non-equilibrium kinetic stage of evolution and to the final equilibration.   The full text >>

Quantum coherence in nonequilibrium systems and nanostructures

Quantum coherence due to cooperative scatterings is studied. Of particular interest are effects of backscatterings on bulk transport properties of electrons in disordered media.
Effects of decoherence and dephasing of electrons interacting with optical phonons in quantum dots out of equilibrium are examined with non-equlibrium Green functions and transport equations.   The full text >>

Quantum critical behavior and phase transitions in itinerant systems

Low-temperature quantum critical behavior where two or more noncommuting operators remain relevant are studied with many-body diagrammatic techniques. The objective is to understand and quantitatively describe admissible types of the critical behavior of vertex functions in interacting and disordered itinerant systems.   The full text >>

Strong electron correlations

Electron correlations are studied in tight-binding models with a screened local interaction of the Hubbard type. Advanced summation methods of Feynman diagrams for two-particle Green functions are the core of our interest. Various simplified forms of parquet equations mixing self-consistently multiple electron-electron and electron-hole scatterings are used to describe peculiarities of the strong-coupling regime.   The full text >>

Mappings of ab-initio systems on effective models

A mapping of the total energy of electrons in magnetic materials and alloys on Heisenberg and Ising-like models is utilized to describe bulk and surface magnetic ordering. The theory is applied to dilute metallic and semiconducting magnetic materials, phase diagrams of layers of alloys, and theoretical explanation of ferromagnetism of thin films on a non-magnetic substrate.   The full text >>

Dilute magnetic semiconductors

Dilute magnetic semiconductors are prototype materials with structural, magnetic, transport, and optical properties determined by combined effects of disorder, electron correlations, and hybridization. Our theoretical study, based on density-functional theory, aims at facilitating magnetic behavior of DMS by optimizing the electronic structure and by controlling native defects and intentional co-doping. Starting from (Ga,Mn)As, we are interested in non-traditional DMS based, e.g., on mixed III-V semiconductors and I-II-V compounds.   The full text >>

Ab-initio electronic structure calculations

Electronic structure of complex materials with unusual properties is studied with TB-LMTO, FP-LAPW, and pseudopotential ab-initio density-functional methods. The calculations are used to predict new materials with potential applications. Relativistic effects and correlation-induced dynamical fluctuations in the electronic structure of alloys, surfaces, interfaces, interlayers and multilayers are taken into account. Real-space finite-element method applicable to nonperiodic structures is being developed.   The full text >>

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