Research follows two general themes. In the first, we are studying the properties of conductors and superconductors which are highly disordered and have reduced dimensionality. We deposit ultra thin films (as thin as one atomic layer) on cold substrates and study their conduction properties. Depending on various properties (thickness, temperature, material) these films can be metallic, insulating or superconducting. Furthermore, using electron beam lithography techniques developed in our laboratory, we can make these films as narrow as ‰ 100Å (only 30 atoms across). This allows studies in both 2 dimensions and one dimension and puts us, at low temperatures, into the quantum mechanical regime. We are extending our work to include ferromagnetic materials.
The second area of study is on high Tc superconductors. Transport, Hall effect and electron tunneling measurements are employed to shed light on the mechanism responsible for superconductivity in these materials. In addition, we are investigating various device ideas employing these novel materials and the physics knowledge we obtain.
These studies incorporate graduate students in physics and materials science as well as undergraduates.
A. S. Katz, S. I. Woods, E. J. Singley, T. W. Li, M. Xu, D. C. Hinks, R. C. Dynes, D. N. Basov, “Interlayer conductivity in the superconductor: Energetics and energy scales,” Phys. Rev. B, 61, p. 5930 (2000).
A. Frydman, L. M. Merchant, R. C. and Dynes, “Proximity Effects in Quench-Condensed Granular Superconductors and Ferromagnets,” Phys. Stat. Sol. (b), 218, p.173 (2000).
W. Teizer, F. Hellman, and R. C. Dynes, “Density of States of Amorphous GdxSi1-x at the Metal-Insulator Transition,” Accepted Phys. Rev. Lett. 85, p. 848-851 (2000).
O. Naaman, W. Teizer, and R. C. Dynes, “The fabrication of reproducible superconducting scanning tunneling microscope tips,” Rev. of Scientific Instruments 72, p. 1688-1690 (2001).
L. Merchant, J. Ostrick, R. P. Barber Jr., and R. C. Dynes, “Crossover from phase fluctuation to amplitude dominated superconductivity; A model system,” Phys. Rev. B 63, 134508 (2001).