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Cardona Queisser Simon 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 (CV). He retired in 2000. His department was mainly concerned with optical spectroscopy of semiconductors and high-Tc 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-Tc 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 (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. Arndt Simon
	Phone:	+49 (0)711 6 89 - 16 40
	Fax:	+49 (0)711 6 89 - 10 10
	E-Mail:	A.Simon@fkf.mpg.de

SIMON'S department emphasized the investigation of metal-metal bonding with main group, d- and f-metals. The purpose of the work is on one side the development of structural concepts (e.g., condensed cluster concept) and on the other side the search for new materials, their phase relationships and connections between structure, chemical bonding and properties. Targets were metal-rich compounds of transition metals, particularly oxides and halides, reduced rare earth metal halides, hydride, carbide, boride, boride carbide, aluminide and silicide halides of the rare earth metals, alkali and alkaline earth metal suboxides and subnitrides. Electron microscopy is used to characterize microcrystalline phases up to full structure refinement as well as analysis of real structure. Superconductivity is of special interest following a chemical view of the phenomenon in terms of a tendency towards pairwise localization of conduction electrons in a flat band-steep band scenario. New colossal magnetoresistance materials result from an interplay of d- and f-electrons. Other fields of interest were structures of molecular crystals, in particular, in situ grown crystals of gases and liquids, with experimental techniques like diffractometry with X-rays and neutrons, high-resolution transmission electron microscopy, electron crystallography and measurements of magnetic susceptibility as well as electrical transport properties used.

 
 

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