Professor Clarke’s group currently focuses on the physics of novel epitaxial materials, including magnetic and ferroelectric thin-film structures. Questions of interest relate to the unusual properties of thin-film materials that are increasingly important for microelectronics applications. Ongoing research projects include the following:
· Ferroelectric heterostructures for their extraordinary dielectric behavior and symmetry-breaking structural transitions
· Magnetic nanostructure studies aimed at understanding the link between structural and magnetic anisotropy in materials for high-density recording applications
· Diamond-like boron nitride films for field emission and neutron detection applications. This work is in collaboration with the Space Physics Research Lab.
Experimental facilities available for this work include several ultrahigh vacuum chambers instrumented for vapor deposition, ultrafast laser ablation, and ion-assisted plasma growth techniques. In-situ diagnostics for thin-film growth include scanning tunneling microscopy (STM), Reflection High Energy Electron Diffraction (RHEED), and wafer curvature stress monitoring. Thin-film Kerr magnetometry is also available, including a novel time-resolved MOKE instrument in collaboration with the OPIL and FOCUS ultrafast optics facilities in the Randall Lab. Much of the structural work is carried out at the Advanced Photon Source, a state-of-the-art synchrotron x-ray facility located at Argonne National Lab. The work is supported by private industry, the U.S. Department of Energy Office of Basic Energy Sciences, and the National Science Foundation.
Professor Clarke is a Fellow of the American Physical Society.
Transient Strain Driven by a Dense Electron-Hole Plasma, (M.F. DeCamp, D.A. Reis, A. Cavalieri, P.H. Bucksbaum, R. Clarke, R. Merlin, E.M. Dufresne, D.A. Arms, A.M. Lindenberg, A.G. MacPhee, Z. Chang, B. Lings, J.S. Wark, S. Fahy), Phys. Rev. Lett. 91, 165502-1-165502-4, (2003).
Effects of Three-Dimensional Atomic Forces in Topographical Imaging of Atoms with an Atom Force Microscope, (W.L. Wang, S.J. Hu, and R. Clarke), Phys. Rev. B 68, 245401 (2003).
Direct Determination of Epitaxial Interface Structure: Gd2O3 Passivation of GaAs, (Y. Yacoby, M. Sowwan, E. Stern, J. Cross, D. Brewe, R. Pindak, J. Pitney, E. Dufresne and R. Clarke), Nature Materials 1, 99 (2002).