Faculty of Physics and Earth Sciences

Research Activities at the Faculty

The research at the Faculty of Physics and Earth Sciences in 2007 is characterized by an extension of national and international collaborations and major investments. In the second round of the federal “Initiative of Excellence” the Physics division together with other partners was successful in establishing the Graduate School “BuildMona”. Furthermore, a large number of projects has intimate connections with regional and national focal points within the Free State of Saxony. With the appointment of Prof. Dr. Vera Denzer (Anthropogeography) teaching and research in this very popular discipline is strengthened.

Collaborative Research Programs

Physics of Interfaces
The group coordinates the EC-sponsored project TROCAT (Prof. Dr. Jörg Kärger), within nine groups from five countries are jointly exploring the interaction between molecular diffusion and conversion in heterogeneous catalysis. The so far attained results of both fundamental and industrial relevance were unconceivable without this strong experimental basis within the Magnetic Resonance Centre of University Leipzig. Theses activities are continued within a Network of Excellence of the 6th frame EC programme INSIDE-PORES. With the special focus on diffusion in zeolites, the group initiated the establishment of an International Research Group (British / French / German), jointly sponsored by EPSRC, CNRS and DPG. The activities of this group will be of particular benefit for the International Research Training Group, dedicated to “Diffusion in Porous Media”, which started to operate in summer term 2004 and comprises groups from Physics Institutes and of Chemical Technology of University Leipzig, together with colleagues of the Universities of Amsterdam, Delft and Eindhoven.

Research Unit 522 [http://www.uni-leipzig.de/~for522/]
In Research Unit 522 (FOR 522) funded by Deutsche Forschungsgemeinschaft (DFG) Universität Leipzig, Leibniz-Institut for Surface Modification, Leipzig (IOM) and Max-Planck-Institute for Microstructure Physics, Halle/S jointly investigate novel nanostructures for future applications in nanomechanics, sensorics, photonics and electronics. We pursue a novel kind of architecture of micro- and nanostructures. These structures shall fully use the three-dimensional space, first as single elements, later also as networks. New degrees of design freedom become possible with regard to strain management and interconnectivity. This approach is followed for the fabrication of nanowires and microcolumns, spirals, scrolls, cylinders or similar structures. Their novel functionality makes them elementary building blocks for the above mentioned applications.
The structures envisioned by us are constructed in free space. They shall be fabricated with minimum use of patterning technology, employing the principles of self-assembly and directed self-assembly. This bottom-up approach allows us to create novel structures which cannot be created by top-down technology, e.g. spirals and structures with extreme aspect ratio.

Our structures are fundamentally different from nanoparticles, clusters, mesoscopic inhomogeneities, nanostructures embedded in a planar matrix (quantum dots) or a liquid (colloidal quantum dots) , which are currently under intense investigation. The complex, three-dimensional design of our building blocks can contain curvatures and leads to properties which cannot achieved any other way. The size scale of the structures depends on the physical properties such as electron or photon confinement or phase stability.

Leipzig Graduate School of Natural Sciences - Building with Molecules and Nano-objects (BuildMoNa) [www.buildmona.de]
The Graduate School “Leipzig School of Natural Sciences – Building with Molecules an Nano-objects (BuildMoNa)” is funded within the German Excellence Initiative. The School focuses on interdisciplinary graduate education through top-level, synergistic research. Our materials research concept is based on a “bottom-up” approach. Progressive building blocks, such as nano-objects, smart molecules, polymeric scaffolds, and active proteins, will be combined – preferentially by self-organization – to create fundamentally new classes of materials that are inspired by active, adaptive living matter, and that are environmentally friendly, highly efficient, low-cost devices serving multifunctional purposes for a steadily more diversified modern society. The paradigm shift from uniform bulk materials towards nanostructured multifunctional materials that emerge from combinations of smart molecules, proteins, and nano-objects is essential for the future knowledge transfer from fundamental to applied sciences.

The Graduate School's main objective is “Building with Molecules and Nano-objects (BuildMoNa)”. The central themes will connect interdisciplinary, fundamental Research, the use and development of suitable, novel Methods, and interdisciplinary graduate Training.
In our Research, “hard” (synthetic molecules and crystalline nanostructures) and/or “soft” (polymers, biomolecules) building blocks will be directly connected or organized to complex structures by scaffolds to reveal new building principles and to produce new, desired materials with innovative applications.

For the success of such research the development of novel Methods for building and characterization of new materials is essential.

Recognizing the need for a new breed of interdisciplinary scientists the Training program aims at promoting interdisciplinary exchange in the natural sciences by high-quality education in material- and method-oriented subjects.

The cooperation with international scientific and industrial partners, as well as other research institutions in the Leipzig area, will complement and broaden the school's expertise and outreach by establishing a unique research and training network for the doctoral candidates.

The school aims to attract highly motivated and excellent applicants with BSc, MSc or equivalent degrees from around the world to engage in top-level research and high-quality training which will propel them into important positions in academia and industry.

Collaborative Research Project (Sonderforschungsbereich) 762 “Functionality of Oxide Interfaces” [http://www.physik.uni-halle.de/FG/index.html]
The joint initiative of Martin-Luther-Universität Halle (Sprecher-Univ.), Universität Leipzig, Max-Planck-Institute for Microstructure Physics, Halle/S and Otto-von-Guericke Universität Magdeburg is devoted to the preparation, analysis and understanding of interfaces in oxide systems and their use in advanced heterostructures. Functional properties are investigated with a perspective for magnetoelectronic, spinelectronic and multiferroic devices. Scientific work in the SFB begins 1.1.2008.

SANDiE Network of Excellence “Self-Assembled semiconductor Nanostructures for new Devices in photonics and Electronics” (Coordinator: Prof. Dr. Marius Grundmann)
The SANDiE Network of Excellence is dedicated to the study of self-assembled nanostructures (SAN) and increases dialogue, exchange of expertise and access to infrastructure, thereby integrating European research resources. The network started its activities in July 2004 and will be funded for a period of four years by the European Commission with 9.2 million Euros. SANDiE integrates 31 partners in 14 European nations – among the partners are 17 universities, nine research institutes and five industrial partners. Universität Leipzig coordinates the network.

It is the goal of SANDiE to secure the world-wide leading position in the scientific field of SAN by overcoming fragmentation. Therefore, human resources, facilities, educational activities and exploitation are integrated by the partners.

The scientific research fields of the network cover SAN for long-wavelength laser emission, SAN for inter-sublevel transitions and SAN for single photon communication. Novel structures and materials for SAN are investigated and simulations of SAN growth, physics and devices are performed.

For Universität Leipzig, the Faculty of Physics and Earth Sciences as well as the Faculty of Chemistry and Mineralogy (Semiconductor Chemistry Group) are participating in SANDiE. The focus of research is the growth of ZnO and Ga(As,N) nanostructures, nano-spintronics in InGaAs/GaAs quantum dots and the fabrication and characterization of GaAs nanorolls.

EU-RTD Project NANODERM (Coordinator: Prof. Dr. Tilman Butz)
Within a collaboration between institutions at Bordeaux, Lisbon, Kraków, Debrecen, Lund, and Antwerp electron- and ion microscopy is employed to investigate to what extent nanoparticles can penetrate the skin and enter into vital tissue. In addition, the response of living cells in contact with nanoparticles is studied.

International Max Planck Research School (IMPRS) and Centre for Theoretical Sciences (NTZ)
The Institute for Theoretical Physics works closely together with the Max-Planck Institute for Mathematics in the Sciences and the Centre for Theoretical Sciences (Director: Prof. Dr. Wolfhard Janke) as part of the university´s Centre for Advanced Study. In particular scientists of the Institute for Theoretical Physics take an active part in the International Max Planck Research School of the MPI MIS.

Cooperations of the Physics-Institutes

The most important extra-universitary research partners at Leipzig are (cooperating Institutes in parentheses):

• Institut für Oberflächenmodifizierung Leipzig (Institute of Experimental Physics I and II),
• Max-Planck-Institut für Mathematik in den Naturwissenschaften Leipzig (Institute of Theoretical Physics, Institute of Experimental Physics II),
• Max-Planck-Institut für Kognitions- und Neurowissenschaften (Institutes for Experimental Physics I and II)

In addition, there are numerous national and international collaborations which cannot be listet here in full.

• Leibniz - Institute of tropospheric research Leipzig
• DLR Oberpfaffenhofen
• Deutscher Wetterdienst
• Leibniz - Institute of Atmospheric Physics at University of Rostock
• Institute for Energy and Environment gGmbH, Leipzig
• GeoForschungsZentrum Potsdam (GFZ)

• Leibniz-Institut für Länderkunde, Leipzig
• Helmholtz-Zentrum für Umweltforschung GmbH – UFZ, Leipzig-Halle
• Kommission für Landeskunde der Sächsischen Akademie der Wissenschaften, Leipzig
• Ungarische Akademie der Wissenschaften, Budapest (Ungarn)
• Universitäten Pernambuco (Brasilien), Havanna (Kuba), Warschau (Polen)

Publications

The Faculty of Physics and Earth Sciences demonstrates its performance with about 300 publications (of which a large number represents original work published in refereed journals and international monographs).

Research Areas and Organisation of the Faculty

The broad research spectrum of the faculty includes the following areas, structured into the following institutes and divisions:

Institute of Theoretical Physics
(Director: Prof. Dr. Gerd Rudolph)

Computer-Oriented Quantum Field Theory (Speaker: Prof. Dr. Wolfhard Janke)
The Computational Physics Group performs basic research into classical and quantum statistical physics with special emphasis on phase transitions and critical phenomena. In the centre of interest are currently the physics of spin glasses, diluted magnets and other materials with quenched, random disorder, soft condensed matter physics with focus on fluctuating polymers and interfaces, and biologically motivated problems such as protein folding, aggregation and adhesion to solid substrates. Investigations of fluctuating geometries with applications to quantum gravity, the statistical mechanics of complex networks and the physics of magnetic materials using quantum Monte Carlo algorithms are also performed.

Quantum Field Theory and Gravitation (Speaker: Prof. Dr. Gerd Rudolph)
We study relativistic quantum field theories and gravity with special focus on the mathematical structure of gauge theories and gravity (stratified structure of the classical configuration space, nonperturbative quantization methods, general covariant quantum field theories, non commutative geometry) and perturbative methods (general gauge theories, ground state energies, Casimir effect).

Theory of Elementary Particles (Speaker: Prof. Dr. Klaus Sibold)
In the realm of elementary particle theory quantum field theoretic methods are being applied mainly to renormalization theory, to supersymmetric theories, to quantum chromodynamics, and to lattice gauge theory. Close to experimental work at particle accelerators is the theoretical investigation of structure functions of hadrons and the development of programs to simulate hadronic scattering processes.

Theory of Condensed Matter (Speaker: Prof. Dr. Ulrich Behn)
Research in condensed matter theory is performed in three subgroups. Stochasticity and structure formation are investigated in noise induced phenomena in non equilibrium systems. Nonlinear dynamics and statistical physics are applied to study Th1-Th2 regulation and idiotypic networks of the immune system. Unconventional magnetic properties of transition metal oxedes due to strong electron correlations are studied. In April 2005 Prof. Klaus Kroy joined our group working on nonequilibrium dynamics of various soft matter systems. The problems range from spontaneously developing desert sand dunes , gels of adhesive colloids and proteins, viscoelastic mechanics of the dytosceleton to the behaviour of single DNA molecules under strong external fields.

Statistical Physics (Speaker: Prof. Dr. Manfred Salmhofer)
Main research areas are the construction of interacting models of quantum field theory and quantum statistical mechanics using renormalization group methods and the theory of correlated fermion systems in the context of high-temperature superconductivity.

Molecular Dynamics/Computer Simulations (Speaker: PD Dr. Horst Ludger Vörtler)
Structural data, thermodynamic quantities, the phase behaviour and transport coefficients of many particle systems and their dependence upon intercrystalline and intracrystalline interactions and upon the structure of the molecules and surfaces are investigated. Methods of statistical physics, of molecular simulations and of percolation theory are employed.

The theory is extended to inhomogeneous and non-equilibrium systems including mixtures and nonlinear effects. The mutual coupling of different molecular phenomena, such as adsorption, wetting, mobility, chemical reactions, self diffusion and transport diffusion will be taken into account.

Institute of Experimental Physics I

The Institute's work focuses on research into “soft condensed matter”. It covers a wide range of very different materials such as lipid membranes, liquid crystals, artificial polymers and biological macromolecules. Their physical characteristics are studied as individual molecules, together with other molecules of the same kind, and as host/guest systems.

Molecular Physics (Speaker: Prof. Dr. Friedrich Kremer)
This division deals with the structure and dynamics of supramolecular arrangements like those formed by liquid crystals and low-molecular and polymer compounds. These systems possess a high degree of co-operation, which is reflected in the formation of macromolecular superstructures.

Interface Physics (Speaker. Prof. Dr. Jörg Kärger)
This division investigates the interaction of molecules with the surfaces of solids, especially the inner surface of microporous solids (particularly zeolites). This work is of immediate practical significance in numerous technical processes such as low-energy and environmentally sustainable substance separation and refinement, the development of functional materials, and prospecting for mineral deposits.

Soft Matter Physics (Speaker: Prof. Dr. Josef Käs)
Since the great discoveries of Watson and Crick, life science has provided us with a tremendous insight into the molecular basis of processes occurring in biological cells. A significant part of this new knowledge was obtained by utilization of innovative physical techniques. The 25,000 genes coded in the human genome result in a corresponding number of proteins. Possible interactions between these species can be estimated as not yet accessible to a quantitative description. By identifying cellular subunits acting as independent functional modules this complexity becomes tractable and the fundamental physical principles of these modules can be studied. A prototypical example for such a module is the intracellular scaffold known as the cytoskeleton. The cytoskeleton is the key structural element in cellular organization and is an indicator of pathological changes in cell function. It is a compound of highly dynamic polymers and active nano-elements inside biological cells that mechanically and chemically senses a cell’s environment. In my laboratory, its physical properties are characterized – among others – by modern atomic force microscopic (AFM) techniques. The cytoskeleton generates cellular motion and forces sufficiently strong to push rigid AFM cantilevers out of the way. This active, soft condensed matter, with structures on nanometer and micron scales representative of individual proteins and cells, calls forth new biological and polymer physics. My research group’s specific goals center on unraveling this new physics of the cytoskeleton. One of the most appealing aspects of such interdisciplinary research is that it simultaneously provides fundamental advances in science as well as novel applications in medical fields such as oncology, neurology, and regenerative medicine. Furthermore, the insight into this active biological matter will cross-fertilize with nano-sciences by providing the blue prints for the assembly of nano-constituents into complex molecular machines.

Molecular Nanophotonics (Speaker: Prof. Dr. Frank Cichos)
The challenge of experimental physics on the nanoscale is to access local phenomena, that occur for example at interfaces, at specific molecular sites or at certain places within nano-structured materials. These local phenomena may control molecular dynamics, drive self-organization, cause charge separation or alter light propagation. Their importance extends to almost every field involved in future nanotechnology.

The research of the molecular nano-photonics group thus aims at the development and application of optical techniques to access nanoscale (dynamical) processes in various fields such as chemical physics, biology or semiconductor physics. The understanding of these dynamical processes shall ultimately lead to a control over single molecules and other nano-objects by applying heat, flow, shear forces, electric fields or current.

The main experimental tool within our research is optical single molecule detection by ultra-sensitive microscopic techniques including time-resolved confocal microscopy, wide-field fluorescence or photothermal microscopy. Single molecules or semiconductor quantum dots provide the ideal local probes to access nanoscale physical properties inside materials while keeping the information on the heterogeneity of the system. Using these techniques our current projects focus on hydrodynamic boundary conditions in nanofluid systems, heterogeneous single molecule dynamics in polymers, photothermal detection and manipulation of nano-objects, emission of single photon sources in photonic crystals and photo-induced processes in II-VI semiconductor nanocrystals.

Institute of Experimental Physics II

The Institute's underlying work comprises basic research into solid-state physics, with close links to materials research, chemical physics, biophysics and the Earth Sciences being pursued.

Semiconductor Physics (Speaker: Prof. Dr. Marius Grundmann)
This division mainly deals with the optical characteristics of semiconductors (e.g. GaAs and ZnO), and chiefly studies micro- and nanostructured systems and individual atomic layers. Practical developments are carried out in the area of optoelectronics and mobile communication.

The electronic properties of quantum-solids in which the electrons exhibit strong correlations with each other or with the lattice are particularly rich and will be of special importance in future functional materials. In addition, such solids are challenging for experiment, as well as theory, as the twenty-year history of high-temperature superconductivity shows: we still do not understand the electronic structure of these systems. One particular aspect of strongly correlated electronic materials is their tendency towards nano-scale electronic phase separation. Even in perfect lattices, electronic nano-structures can form. The investigation of such materials requires the use of methods that can give detailed information. Here, magnetic resonance (on nuclei and electrons) is of particular interest as they not only have atomic scale resolution, but also yield bulk information in contrast to surface techniques. As one might expect, the material properties can be quite different from the bulk near the surface.

Nuclear Solid State Physics (Speaker: Prof. Dr. Tilman Butz)
Solutions for current problems on specific topics of material science and bio-medical research need modern and established methods using ion beam analytics as well as nuclear probes.

For these researches we use the high-energy-nano-probe LIPSION with specifications which are unique in Germany. Current researches are focused on spatially resolved trace elements analysis in neuroscience, determination of the response of living cells to single ion bombardment, ion beam analysis of micro- and nano-structures, as well as ion beam modifications.

The perturbed gamma-gamma-angular correlation (TDPAC) is used to determine the nuclear quadrupole interactions of materials like TiO2 bulk material and TiO2 nano-particles. This method is also able to determine in-vitro the solubility of these nano-particles in body fluids without any separation of the particles and solution. This information is absolutely necessary to determine probable health risk after incorporation of nano-particles. Coordination studies of 199mHg in de-novo designed peptides were carried out at ISOLDE/CERN.

Superconductivity and Magnetism (Speaker: Prof. Dr. Pablo Esquinazi)
The Division of Superconductiviy and Magnetism is engaged in the study of basic properties of various magnetic and superconducting materials. At present the research activities focus on: (1) the study of the magnetic properties of proton irradiated graphite samples, (2) the investigation of the magnetotransport properties of multigraphene, (3) the study of spin-dependent phenomena in magnetic oxide heterostructures and (4) the measurement of the transport properties of superconducting micro- and nanostructures.

Didactics of Physics (Speaker: Prof. Dr. Wolfgang Oehme)
This department focuses on aspects of teaching traditional and modern topics of physics at schools. Empirical testing is carried out, while forms of learning in physics classes, open and interdisciplinary teaching, and ways of using modern media are all studied.

Institute of Meteorology
(Director: Prof. Dr. Gerd Tetzlaff)

General Meteorology (Speaker: Prof. Dr. Gerd Tetzlaff)
Research includes the description of precipitation using mesoscale prediction models, the analysis of extreme rain and precipitation events, variability of precipitation in connection with climatic change and investigations of the consequences of extreme weather conditions. Near surface observations, radar and satellite data are used to validate meteorological models.

Theoretical Meteorology (Speaker: Prof. Dr. Werner Metz)
The research is focussed on the natural atmospheric variability with time scales from weeks to decades, in particular on the forcing and propagation of large-scale flow systems in the atmosphere and on the role of atmospheric interaction processes. Mechanistic models and observational data are both used to investigate the importance of such phenomena for the General Atmospheric Circulation.

Upper Atmosphere (Speaker: Prof. Dr. Christoph Jacobi)
Research includes numerical simulation of the middle atmosphere from the Stratosphere to the thermosphere using different circulation models of the atmosphere. Work includes the construction of reference atmospheres, analysis of trends and the influence of solar variability on the upper atmosphere. To this end, own ground-based measurements of upper atmosphere parameters as well as global satellite data are used.

Acoustics of the atmosphere (Speaker: Jun. Prof. Dr. Astrid Ziemann)
Focal point of research is modelling and observation of sound propagation parameters as well as the assessment of sound immissions in consideration of the atmosphere’s structure various systems for monitoring of meteorological and sound field data using conventional and new remote sensing techniques (acoustic tomography) are developed or applied in line with third-part funded projects.

Institute of Geophysics and Geology
(Director: Prof. Dr. Werner Ehrmann)

Research concentrates on environmental and engineering geophysics, theoretical geophysics and the geology of the Cenozoic Period. Close co-operation with German research institutions takes place with the Centre for Environmental Research Leipzig-Halle, the Potsdam Geo-Research Centre, the Freiberg Mining Academy, the Saxonian Department of Geology, the Alfred Wegener Institute for Polar and Marine Research and the Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover. Co-Operation with international partners is even more diverse.

Geophysics (Speaker: Prof. Dr. Michael Korn)
Environmental and engineering geophysics explores the Earth's upper crustal structure by seismic, ground penetrating radar, electric and electromagnetic methods. Our focus is on geologic barriers, underground reservoirs, contaminated sites, unconsolidated rocks, cavities, groundwater, river dikes, and disused mines along with their effects on urban environment. Furthermore, physical properties of rock samples are measured to link physical and petrophysical parameters. Theoretical Geophysics explores the deep structure of the Earth as well as seismic and volcanic sources. Seismic wave propagation in complex structures is investigated. A local seismic network continuously monitors the tectonically active areas in Saxony. The Geophysical Observatory Collm conducts long term measurements of seismic and magnetic fields. It is part of the German Regional Seismic Network, and of the global seismological broadband network.

Geology (Speaker: Prof. Dr. Werner Ehrmann)
The research of the geology division centres on the Earth's history of the last 100 million years. Fundamental questions of the geology and palaeontology of the late Cretaceous, Tertiary and Quaternary periods are studied, with special emphasis on the reconstruction of the palaeoclimate, palaeoenvironment and palaeobiogeography. We investigate terrestrial, limnic and marine archives in the surrounding of Leipzig and in other key regions (e.g. Antarctica, Mediterranean Sea, South Atlantic) by a variety of geochemical, sedimentological, mineralogical and palaeontological methods. Applied research is performed in environmental geology and hydrogeology in particular in SE Germany. The Geological/Palaeontological Collection forms an important basis for both teaching and research, as well as for PR work.

Institute of Geography
(Director: Prof. Dr. Reinhard Wießner)

Work concentrates on spatial structures and processes in mankind’s habitat. Methods from the social, economical and natural sciences are used to explore, evaluate and forecast the spatial changes caused by natural processes and human activity.

Human Geography, Regional Geography and Regional Planning (Speaker: Prof. Dr. Vera Denzer)
Human Geography deals with questions of Urban Geography, Social Geography, and Economic Geography. The main interest is the impact of social, economic and technological change on urban and regional structures. Key topics are analysing processes of transformation and restructuring in towns, cities and regions in Eastern Germany and East Central Europe. Research topics refer to housing studies, transport and mobility, retail trade, economic development and questions of sustainable urban and regional development. In consideration of cultural geographies the questions of cultural landscape studies and symbolic geographies are in the focus of research. Regional Planning mainly focuses aspects of regional development and planning in Central Germany.

Physical Geography und Geoecology (Speaker: Prof. Dr. Jürgen Heinrich)
Physical Geography and Geoecology addresses problems of landscape dynamic and development (genesis) in different kinds of landscapes. Questions deal with soil development and the substance migration of pollutants in hydrological catchment areas, protection areas and agricultural land, considering the ecological, economical and social conditions. Another field of work is urban ecology. Referring to sustainable development of landscapes and landscape planning, concepts for the analysis, the evaluation and the management of landscapes are developed.

Geoinformatics und Remote Sensing (Speaker: Prof. Dr. Werner Kirstein)
Remote Sensing and Geoinformatics deal with innovative computer-based methods of geographical research. Geographical climate studies of the relations between solar activity and main climatic elements by analysis based on GIS (geographic information systems) and trend analysis on regional climatic change are an concrete field of research. Topics of global and regional problems of the climate change are continued with the goal of a factual discussion in science and public.