Research Interests

The research of our group focuses on the investigation of optical and magneto-optical properties of model low-dimensional, molecular, and nanoscale solids with the overarching goal of understanding the consequences of spin-lattice-charge coupling, microscopic strain, magnetic field, and chemical substitution on local structure and functionality. Specific efforts concentrate on elucidating mechanisms for the magneto-dielectric effect and exploiting the complex phase diagrams of frustrated materials to increase the high frequency response, probing unusual manifestations of spin-lattice-charge-orbital coupling, "beyond Heisenberg", and hydrogen bonding effects in chemically-related magnetic materials, elucidating charge and spin ordering patterns in bulk vs. nanoscale materials, and quantifying connections between local and bulk properties of engineering interest such as negative thermal expansion or solid state lubrication. These structure-property issues are at the interface between the traditional fields of solid state chemistry and condensed matter physics. They are also at the heart of our ability to understand, design, and control advanced materials.

We have strong research collaborations at several National Laboratories. These include Argonne National Lab, Brookhaven National Lab, the National High Magnetic Field Laboratory, and Oak Ridge National Laboratory. We have many active domestic and international academic collaborations as well. Students in my Group benefit significantly from these collaborations.

Our group has strong external support from the National Science Foundation (through the Division of Materials Research), the U.S. Department of Energy (Materials Science Division, Basic Energy Sciences), and the JDRD Program sponsored by the University of Tennessee.

Our Facilities

Our lab (2000 sq. ft) is in the Science and Engineering Research Facility at the University of Tennessee. It is fully equipped for a variety of spectroscopic measurements. Major equipment includes: a Bruker 113V Fourier Transform Infrared Spectrometer (35-5000 cm^-1) with reflectance stage, Perkin-Elmer far- and mid-infrared polarizer/analyser set, high sensitivity liquid helium cooled far (bolometer) and mid-infrared (boron-doped Si) detectors made by Infrared Labs, and a low-temperature cryostat equipped with transfer line and temperature controller. An infrared microscope system compliments the capabilities of the Bruker 113V and provides the capability to study very small samples. A very far-infrared/near mm wave polarizing spectrometer that provides important support for the low-frequency side of the Bruker 113V (2 - 100 cm^-1). We also have a Perkin-Elmer Lambda-900 grating spectrometer which covers the near-infrared, optical, and ultra-violet regimes (4000 - 60000 cm^-1). A reflectance / transmittance stage incorporates our open-flow cryostat for variable temperature measurements. Polarizers are available to cover the full frequency range of the instrument. A refurbished aluminum evaporator can be used to coat rough samples and correct for surface scattering. We recently acquired a 15 T superconducting magnet. Appropriate probe development is on-going.