LIST OF RESEARCH LABORATORIES IN THE DEPARTMENT OF PHYSICS, CAS
The Nanophysics and Surface Science Laboratory
Matthias Batzill, Assistant Professor of Physics, CAS
In this laboratory, we investigate condensed matter at the atomic scale. The surface of a material is where the action is; at a surface the material interacts with its environment and thus many chemical and physical processes occur at the interface between a solid and a different medium. Our goal is to understand the structural and electronic properties of surfaces and to tune these properties in order for the surface to perform new or improved functions. Currently investigated surface-functional materials are metal oxides for their use as solid state gas sensors and for solar energy conversion. Modification of surfaces with nanoclusters to improve their functionality is one approach to improve and create new functionalities. Nanoclusters are aggregates of atoms in the realm between molecules and bulk materials. In this size range condensed matter exhibits new properties, which can be conveniently tuned by controlling their size. In our laboratory we assemble clusters atom by atom in the gas phase and subsequently place them on a support material. This allows investigating the cluster-support interaction and the cluster size- properties relationship. Most of the sample preparation and characterization is done under ultra high vacuum conditions to ensure the integrity of the samples under investigation. In addition to the in-house measurements; some supplementing photoemission and X-ray absorption studies are performed at synchrotron facilities.
Laser Physics and Single Crystal Fiber Growth Facility
Nick Djeu, Professor of Physics, CAS
This laboratory is equipped with a variety of cw and pulsed lasers including frequency-doubled Nd:YAG pumped Ti-sapphire laser, Ar+-pumped dye laser and frequency- stabilized ring dye laser to study nonlinear optics and develop novel fiberoptic devices. Recent research includes study of upconversion processes in rare earth doped laser crystals towards the development of infrared solid state lasers and the invention of a new type of thermal source with potential capabilities in the fabrication of micro-mechanical systems and surface modification on a microscopic scale. This laboratory also uses the laser-heated pedestal growth method to grow rare earth doped crystals in small rod form for spectroscopic and energy transfer studies andoptical crystalline material in long fiber form for fiber-optic applications. In particular, techniques for growing high optical quality, high purity sapphire fibers have been developed. Examples of potential applications for sapphire fibers include medical laser delivery and fiber-based sensors for hostile environments. The facility has two growth stations, fabrication equipment, x-ray diffractometer, microinterferometer, and light sources and spectrometer for optical/spectral characterization.
Materials Physics Laboratory
Srikanth Hariharan, Associate Professor of Physics, CAS
This laboratory is equipped with a state-of-the-art Physical Property Measurement System (PPMS) for studying the electrical and magnetic properties of novel materials. Investigations of the material properties are conducted over a wide range in temperature (2K<T<350K) and applied magnetic fields up to 7 Tesla. In addition, the frequency-dependent electromagnetic response is probed from DC to 3 GHz. A novel resonant radiofrequency (RF) method has been developed to accurately determine the magnetic anisotropy and switching effects in materials. Current sponsored research projects focus on studies of dynamic magnetic response and high frequency impedance in nanoparticles, thin films, composites and coordination polymers exhibiting molecular magnetism. These technologically important materials are promising candidates as building blocks for the next generation of spin-based electronic devices. Other interests include point contact and tunneling studies in superconducting and magnetic junctions.
Laboratory for Organic Electronic Materials
Xiaomei Jiang, Assistant Professor of Physics, CAS
This laboratory provides materials growth and characterization in the area of organic electronic materials with a particular emphasis on the fabrication and characterization of light emitting diodes and photovoltaic devices for solar cell applications.
Laboratory for Laser Remote Sensing
Dennis Killinger, Professor of Physics, CAS
This Laboratory studies the development of new laser, atmospheric propagation, lidar, and free-space laser telecommunication techniques. Past activities include development of a high power KTP OPO laser remote sensing system to measure atmospheric aerosols, a tunable Ho:YSGG differential absorption lidar system to detect sources and sinks of CO2 in the atmosphere, and the development of large computer based simulation programs for high resolution HITRAN-PC transmission spectra of the atmosphere and LIDAR-PC simulations. Current work involves UV laser induced fluorescence of trace organic and plastic compounds in water, multi-detector heterodyne detection of fiber optics based 1.54 mm communication signals, laser Doppler measurements of structure vibration modes, and freespace atmospheric laser communication studies related to last mile metro and residential IR telecommunication.
Digital Holography & Microscopy Laboratory
Myung (Paul) Kim, Professor of Physics, CAS
This laboratory develops novel instrumentation for optical sectioning or tomographic imaging. The instrument is based on the recently introduced principle of wavelength scanning digital interference holography (DIH). The images are reconstructed from a number of holograms that are digitally recorded while the wavelengths are varied at regular intervals, and the numerical interference of the multiple three-dimensional hologram fields results in tomographic images with narrow axial resolution. The instrument has no mechanical moving parts. The image acquisition consists of N exposures of two-dimensional images, instead of pixel-by-pixel build-up of 3D volume. The range of physical sizes and resolution of objects that can be imaged is readily controlled by proper choice of the wavelength intervals. And with the holographic phase information readily available, further interferometric of holographic image processing is possible. The research program aims to: 1) develop a prototype instrument with key parameters consistent with practical microscopic imaging applications; 2) build up an image gallery for the purpose of applying the imaging methods and the instrument to a wide range of specimens; and 3) develop relevant biomedical application and new techniques. One of the important long-term goals is to develop a compact, versatile, and economical imaging system, which will help further widen the range of applications. With full development of its capabilities, the digital interference holography has a potential to impact the general field of optical microscopy and tomography by providing a simple and versatile mode of acquiring and manipulating three-dimensional digital model of microscopic objects.
The Bio-Nano Research Group
Garrett Matthews, Assistant Professor of Physics, CAS
The work of this laboratory is the investigation of the structure/function relationship in biological systems ranging from the single molecule to the multicellular level. Molecular level structures determine the materials properties of the system, which in turn determines the macroscopic biological function. Using the expertise in atomic force microscopy, fluorescence microscopy, rheology, and other techniques found in the laboratory, the physical properties of single molecules and macromolecules are measured, and bulk models are developed and experimentally tested. These models are used to help explain the biology or pathology of systems. Example projects within the lab include investigations of cell surface and extracellular matrix glycoproteins and glycosaminoglycans through single molecule imaging and force spectroscopy. The data from these experiments is used to develop models for the visCOElastic properties of solutions of these biopolymers which are then tested experimentally. These rheological properties are important for the function of tissues ranging from joint interstitial fluids to lung epithelium and will be used to understand the behaviors observed in these systems. The outcomes of the lab are geared to make significant contributions to biomedicine, and as such require a close collaboration with the Departments of Biology and Chemistry and with the School of Medicine. The work is inherently multidisciplinary, and students develop a broad range of skills from physics, biology, and chemistry.
Spintronics Laboratory:
Casey Miller, Assistant Professor of Physics, CAS
Facilities include multi-target sputtering system for thin film heterostructure growth, electron transport measurements in high magnetic fields (7T) and cryogenic temperatures (~1K). Current interests include spin-dependent tunneling, spin-injection, and spin-polarization measurements, and combine modeling to complement experiments when appropriate.
Laboratory for Advanced Materials and Technology (LAMSAT)
Pritish Mukherjee, Professor and Chair of Physics, CAS
Sarath Witanachchi, Associate Professor of Physics, CAS
Innovations in pulsed laser ablation and plasma processes for the growth of thin films of technologically significant materials including super hard materials, magnetic materials, superconductors, and compound semiconductors for solar cells are explored in this laboratory. Past NSF and DOE sponsored research projects have focused on the application of a dual-laser ablation process discovered in this laboratory to grow large-area, particulate-free films of Cu(InGa)Se2 and ZnO for solar cell applications, and to fabricate diamond and diamond-like carbon structures for MEMS applications. One of the recently funded NSF projects focuses on a hybrid process where chemical self-assembly and physical vapor deposition techniques are combined to grow vertically aligned nano-grained films of superhard materials. Novel optical techniques for high resolution, in-situ plasma imaging, and development of new laser-assisted plasma growth processes are being researched. The research encompasses thin film growth, nanostructures, dynamic optical process diagnostics, thin film analysis, characterization and process modeling leading to the fabrication of single-layer and hetero-structure devices.
Laboratory of Thin Films and Nanostructures
Martin Munoz, Assistant Professor of Physics, CAS
This laboratory is focused on the development of a new generation of materials and nanostructures for electronic and opto-electronic applications. Current research interests include; chalcogenides materials and devices that change their physical properties, such as phase and volume when illuminated, quantum-dot- and superlattice- heterostructures for LEDs, solar cells and quantum cascade lasers. Also of interest is the application of optical techniques, such as photoreflectance, photoluminescence and Raman spectroscopy, in the characterization of semiconductor devices such as hetero-junction bipolar transistors and quantum well lasers.
The Novel Materials Research and Development Laboratory
George Nolas, Associate Professor of Physics, CAS
This laboratory is engaged in the research of crystal growth and the characterization (including structural, optical and transport properties) of novel materials for technologically significant applications. The emphasis is on an understanding of the structure-property relationships of material systems; that is, how crystal structure variations affect the transport, optical, magnetic, superconducting and/or mechanical properties of materials. The laboratory applies this understanding in ‘‘engineering’’ new and novel materials for varying applications. Current research includes novel semiconductors for electronics and optoelectronics applications, thermal properties of ‘‘open structured’’ semiconductors, nanostructure synthesis and assembly approaches, new superconducting materials and magnetic semiconductors. Close collaboration with industry is typical in this interdisciplinary Materials Physics research program that encompasses all aspects of physics and materials science. Students typically acquire a large variety of skills from physics and chemistry and then apply these foundations to areas of applied physics research and development.
Materials Simulations Laboratory
Ivan Oleynik, Associate Professor of Physics, CAS
This laboratory is involved in modeling materials, with particular strengths in innovative modeling at the electronic and atomistic levels. Our research activities are closely linked with experimental work being performed by leading research groups around the world. Our current research projects include molecular dynamics modeling of condensed matter at ultra-high pressures, first-principles modeling of spintronic materials and electron transport in single molecule devices, atomistic modeling of vapor processing of materials. We are primarily concerned with the development of innovative theoretical approaches and computational techniques that allow to carry out meaningful simulations. Being problem-driven and not technique-driven we are able to address the most challenging problems in materials physics that have practical importance for technological advances in 21st century. The laboratory is equipped with 40-processor Beowulf cluster of maximum peak performance of 100 Gflops, several graphics workstations for visualization and processing of results, and a suite of electronic and atomistic modeling software.
Condensed Matter Theory Research Group
David Rabson, Associate Professor of Physics, CAS
This group works in condensed-matter theory, with currently-funded projects in mathematical crystallography and in modeling and statistical mechanics of magnetic heterostructures. In collaboration with Dr. Benji Fisher (Boston College), the group has reformulated Fourier-space crystallography in the language of cohomology of groups and applied the results to a wider class of structures than previously considered. Continuing work focuses on homological invariants of a new kind and their possible physical implications. Magnetic tunnel junctions exhibit a large magnetoresistance that shows even greater promise for applications in reading magnetic media than current technology. Recently, the group has modeled electrical and thermal transport in junctions and has proposed a simple, fast, and inexpensive quality-control protocol for diagnosing and locating defects. Other current research at the nanometer scale includes a statistical-mechanical model of magnetic order in rare-earth heterostructures and a recent study of the ballistic-to-diffusive crossover in quantum wires. The latter may have applications in quantum computing.
Properties of Nanostructured Materials Research Lab
Lilia Woods, Assistant Professor of Physics, CAS
This group conducts research in the field of nanostructured materials with current and potential technological applications. The group applies theoretical methods, analytical as well as computational, to understand and discover properties of quantum dots, carbon nanotubes, and optical microcavities. Current research on quantum dots involves studying properties related to quantum computing. More specifically, we identify processes contributing to the decoherence of possible qu-bits and calculate their coherence times. Our efforts on carbon nanotubes are related to their abilities to absorb and detect other materials such as water, hydrogen, oxygen, aromatic molecules, and in the future biologically related matter. The problem of absorption is extremely important for potential applications, such as storage and detection. Efforts for optical microcavities are directed towards nonlinear emission optical processes used for optical amplification. Our research considers different types of microcavities, such as planar or one-dimensional spin related properties and their applications in optical experiments.
Copyright © 2008 · Materials Science & Engineering
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