Max Planck Institute for Solid State Research: Physics

Abteilung Keimer
Abteilung Kern
Abteilung v. Klitzing
Abteilung Mannhart
Emeriti

Solid State Spectroscopy - Abteilung Keimer

	Prof. Dr. Bernhard Keimer
	Phone:	+49 (0)711 6 89 - 16 50
	Fax:	+49 (0)711 6 89 - 16 32
	E-Mail:	B.Keimer@fkf.mpg.de

Keimer's department studies the structure and dynamics of highly correlated electronic materials by spectroscopic and scattering techniques. Topics of particular current interest include the interplay between charge, orbital and spin degrees of freedom in transition metal oxides and the mechanism of high-temperature superconductivity. Experimental techniques being used include elastic and inelastic neutron scattering, normal and anomalous X-ray scattering, Raman scattering off and in resonance, spectral ellipsometry (including synchrotron radiation as a source), and infrared, Raman, and X-ray measurements under high magnetic fields. Experiments at external neutron sources are carried out on a regular basis, and a spectrometer at the new research reactor FRM-II in Munich has recently been completed. The latter instrument uses a novel combination of triple axis and neutron spin echo techniques to optimize the energy resolution and allow the determination of lifetimes of magnetic and lattice vibrational excitations throughout the Brillouin zone. The group operates a high-magnetic field facility for X-ray scattering at the National Synchrotron Light Source (NSLS) at Brookhaven National Lab (USA). At the ANKA synchrotron in Karlsruhe, the group also operates Fourier ellipsometers for the far infrared spectral range. Close collaborations also exist with the theory and chemistry departments at the MPI-FKF; with the Crystal Growth Service Group where large, high-quality single crystals of oxide compounds are prepared with optical furnaces, and with the Technology Service Group that prepares state-of-the-art oxide heterostructures and superlattices.

Nanoscale Science - Abteilung Kern

	Prof. Dr. Klaus Kern
	Phone:	+49 (0)711 6 89 - 16 60
	Fax:	+49 (0)711 6 89 - 16 62
	E-Mail:	K.Kern@fkf.mpg.de

Research efforts in the Department Kern are centered on nanometer-scale science and technology with a focus on the "bottom-up" paradigm. The physical and chemical properties of nanostructures are unique functions of their size and shape, and can be very different from those of bulk matter. Particularly fascinating phenomena occur if the nanostructures are subject to lateral boundary conditions on a length scale where quantum behavior prevails. The aim of the interdisciplinary research at the interface between physics, chemistry and biology is to gain control of materials at the atomic and molecular level. Of particular interest are self-ordering strategies for hierarchical organization of complex integrated assemblies, molecular nanotechnology, quantum electronic transport and local probe spectroscopy on the atomic scale. As interfacial phenomena play a key role in the understanding of nanosystems, the structure, dynamics and reactivity of surfaces and interfaces are also in the focus of interest. The research program explores new science relevant for future communication, computing, chemical sensing, energy storage and conversion technologies.

Low Dimensional Electron Systems - Abteilung v. Klitzing

	Prof. Dr. Klaus v. Klitzing
	Phone:	+49 (0)711 6 89 - 15 70
	Fax:	+49 (0)711 6 89 - 15 72
	E-Mail:	K.Klitzing@fkf.mpg.de

The electronic properties of heterostructures, quantum wells, superlattices and carbon based quantum structures (graphene, nanotubes), in particular the influence of quantum phenomena on the transport and optical response are the main topics in von Klitzing's department. Optical and transport measurements in magnetic fields up to B=21.5 Tesla and temperatures down to 10 mK combined with TEM/scanning probe techniques are used to characterize the systems. Picosecond sampling techniques are developed for ultrafast time-resolved measurements on nanodevices. The quantum Hall effect is studied by analyzing time-resolved transport, edge channels, the behavior of composite fermions and the response on microwave radiation and surface acoustic waves. Time-resolved photoconductivity, luminescence, and Raman measurements in magnetic fields are methods of characterizing the low-dimensional electronic systems. Coupled two- and zero-dimensional electronic systems are produced by highly specialized molecular beam epitaxy growth and by electron beam lithography. Phenomena like electron drag, exciton condensation, Kondo resonance, Coulomb blockade, ballistic transport, commensurability phenomena in periodically modulated two-dimensional systems and the interaction between electron and nuclear spins are investigated. The detection and generation of terahertz radiation using low-dimensional electron systems is one of the new research activities.

Solid State Quantum Electronics - Abteilung Mannhart

	Prof. Dr. Jochen Mannhart
	Phone:	+49 (0)711 6 89 - 17 94
	Fax:	+49 (0)711 6 89 - 17 96
	E-Mail:	J.Mannhart@fkf.mpg.de

Induced by quantum mechanical phenomena, heterostructures grown from complex materials offer a fascinating potential to create novel electron systems. Many have outstanding properties that are not otherwise offered by nature. The design, growth, and exploration of such electron systems is at the focus of the department Mannhart. The heterostructures are fabricated by building on recent advances made in the quantum engineering of novel materials, using advanced epitaxial growth techniques to deposit complex compounds with atomic-layer precision. The experimental and theoretical efforts are interwoven with the other departments at the Institute. The goal of the research is to unravel the physics underlying artificial electron systems generated by interfaces and superlattice-type structures, to design and realize new ones, and to understand their potential for novel nanoscale devices that use the stunning effects of the quantum world to surpass the limits of today's electronics.

Emeriti

Prof. Dr. Manuel Cardona

Prof. Dr. Hans-Joachim Queisser

Prof. Dr. Peter Wyder

	Prof. Dr. Manuel Cardona
	Phone:	+49 (0)711 6 89 - 17 10
	Fax:	+49 (0)711 6 89 - 17 12
	E-Mail:	M.Cardona@fkf.mpg.de

Cardona was one of the Founding Directors of the Institute. He retired in 2000. His department was mainly concerned with optical spectroscopy of semiconductors and high-T_c superconductors in the form of bulk samples, surface layers, and low-dimensional structures like quantum wells, quantum dots and superlattices. Central to his interests is electron-phonon interaction, a topic of particular relevance to both material classes. Experimental methods used at present are Raman, hyper-Raman and Brillouin scattering off and in resonance, hot luminescence, spectroscopic ellipsometry (including synchrotron radiation as a source), optical measurements in high magnetic fields and under high pressure, photoelectron spectroscopy, scanning tunneling microscopy in ultra-high vacuum and X-ray techniques for surface and interface structure analysis. Close collaborations with the synchrotron laboratories in Hamburg (HASYLAB), Berlin (BESSY), Grenoble (ESRF) and Brookhaven (NSLS), the high pressure, technology, molecular beam epitaxy and crystal growth service groups at the MPI, the High Magnetic Field Laboratory and the Institute Laue-Langevin (ILL) in Grenoble have enabled the group to extend the variety of experimental techniques at its disposal. Surface X-ray diffraction and X-ray standing wave measurements are carried out at HASYLAB, ESRF and NSLS, while at BESSY a vacuum UV ellipsometer (5-35 eV) is operated. At NSLS a Fourier ellipsometer for the far infrared spectral range has been built and optimized for measurements of extremely small samples. At ILL neutron scattering is used to study the lattice dynamics of isotopically pure and disordered single crystals. There is also a substantial theoretical effort in computing the electronic and vibronic band structure as well as electron-phonon coupling parameters of the materials under investigation. Topics of recent activities of the group are the vibrational and electronic properties of various compound semiconductors and superlattices, in many cases with controlled isotopic composition, the structure of semiconductor surfaces in the UHV and at the electrolyte interface, as well as electronic Raman scattering processes and crystal field excitations in high-T_c superconductors. Considerable effort, partly in collaboration with the University of California at Berkeley and the Kurchatov Institute (Moscow) and Simon Frazer University (Vancouver), is spent in the growth and characterization of crystals with tailor-made stable isotope composition which are used to investigate isotope effects on a wide range of physical properties such as phonon dispersion, lattice constant, electronic band structure or thermal conductivity (for cv and list of publications see http://isihighlycited.com).

	Prof. Dr. Hans-Joachim Queisser
	Phone:	+49 (0)711 6 89 - 16 00
	Fax:	+49 (0)711 6 89 - 10 10
	E-Mail:	H.Queisser@fkf.mpg.de

Hans-Joachim Queisser, born 1931 in Berlin, was one of the Founding Directors of the Institute; he retired in 1998. Queisser is a semiconductor physicist. He studied in Berlin, Lawrence (Kansas, USA) and in Göttingen, where he received his Ph.D. in 1958 in experimental solid-state physics. In 1959, he joined Shockley�s Transitor Corporation and worked in the old apricot barn in Mountain View, California - which was the very cradle of silicon valley. His research concerned defects and perfection of silicon single crystals, device principles, p-n junctions, and solar cells. From 1966, he then investigated compound semiconductors at Bell Laboratories in Murray Hill, NJ with emphasis on optoelectronics. He became professor of physics at Frankfurt�s Goethe University in 1966.
In 1969, he was asked to help establish the Stuttgart institute. Queisser maintains strong international ties; he was visitor at Stanford, UC Berkley, the National University of Singapore, the Central Research Labs of Hewlett Packard in Palo Alto, CA, Bell Labs, and Sony Corp. at Yokohama, Japan. He was president of the German Physical Society, sat 13 years on the Senate of the Max-Planck-Society and serves on many industrial boards.
Home address: Knappenweg 21d, D-70569 Stuttgart, phone: +49 (0)711 681511

	Prof. Dr. Peter R. Wyder
	Phone:	+33 - 476 85 56 00
	Fax:	+33 - 476 85 56 10
	E-Mail:	wyder@grenoble.cnrs.fr

Peter Wyder was the head of the Grenoble High Magnetic Field Laboratory, which until December 31, 2004, was operated jointly with the French Centre National de la Recherche Scientifique (C.N.R.S.).
During the first couple of years, there were two separate laboratories, the French and the German part, respectively; these were then put together into one single laboratory on the basis of a contract for collaboration; Frenchmen and Germans working together, with one director and one single technical and scientific policy. This contract of collaboration between the C.N.R.S. and the MPG has ended in 2004. The aim of the laboratory is to provide high magnetic fields with a wide range of scientific instrumentation (temperatures 30 mK to 1000 K, pressures up to 24 GPa, voltages nV to 50 kV, currents pA to several kA, etc.) allowing many interesting investigations. In the years 1990/1991, most of the technical installations were renewed and the dc-power supply was extended from 10 MW to 25 MW. We now have one of the world's most modern power and cooling installation for the generation of high magnetic fields in operation with a 20 MW resistive magnet producing a world record field in the 30 Tesla range in a bore of 5 cm. In addition, the MPG and the C.N.R.S. decided to finance a new hybrid system for fields in the 40 Tesla range. All these magnets guarantee the leading role of the Grenoble HML also in the years to come. In accordance with its mission, the in-house research at the HML shows a considerable diversification into several fields in condensed matter physics, where the use of high magnetic fields is interesting or necessary, such as the study of metals, semiconductors, 2D electronic systems, magneto-optics, high-field NMR and ESR, polymers and all sorts of soft matter and even some biological systems.