Department of Physics Colloquium on February 20, 2002

 

Suresh C. Sharma

Department of Physics, The University of Texas at Arlington, Arlington, Texas

 

 

A “Progress Report” on our recent efforts in the following two areas of research

 

 

EFFECTS OF HIGH PRESSURE ON THE ELECTRONIC, STRUCTURAL, AND VIBRATIONAL PROPERTIES OF C60-BASED FULLERENES

 

 

            I will discuss recent developments leading to the establishment of our new research facility to probe the electronic, structural, and vibrational properties of materials, in particular C60-based fullerenes under extremely high pressures. We have designed, set-up, and tested the performance of several instruments and techniques, including ultra-high vacuum photoemission spectroscopy, high resolution Raman scattering, high pressure (>20 GPa) diamond anvil cell, x-ray diffraction measurements with diamond anvil cell, low-temperature (10 to 295K) electrical conductivity measurements, and thin film growth. I will also present and discuss our preliminary results on: 1) Photoemission spectroscopy measurements of the valence band structures of polymerized thin films of C60 and La0.1C60, 2) Raman spectroscopy measurements of the vibrational properties of C60 compressed under high pressures in a diamond anvil cell.

 

Supported by the Department of Energy and The Welch Foundation

 

 

 

OPTICAL PROPERTIES (SWITCHING BEHAVIOR) OF NANOMETER-SIZE LIQUID-CRYSTAL DROPLETS DISPERSED IN A POLYMER MATRIX

 

 

            Polymer-dispersed liquid crystals (PDLC) constitute an important class of materials with applications in electrically switchable optical devices. For example, light transmission through such a device can be controlled precisely by the application of relatively small voltages. I will discuss fabrication of a simple device, present results on its switching behavior, and speculate on its potential new applications.

 

Supported by the Texas Advanced Technology Program