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Robert C. Dynes
Professor, Physics Dept.
Chancellor of UCSD
Ph.D. McMaster, 1968

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.

Selected Publications:

A.G. Sun, A. Truscott, A.S. Katz, R.C. Dynes, B.W. Veal and C. Gu, Direction of Tunneling in Pb/I/YBCO Tunnel Junctions. Phys Rev. B.. 54, 6734 - 6741 (1996).

F. Hellman, M.Q. Tran, A.E. Gebala, E.M. Wilcox and R.C. Dynes, Metal-Insulator Transition and Giant Negative Magnetoresistance in Amorphous Magnetic Rare Earth Silicon Alloys, Phys. Rev. Lett. 77, 4652-4655, (1996).

P. Xiong, A.V. Herzog and R.C. Dynes, Negative Magnetoresistance in Homogeneous Amorphous Superconducting Pb Wires, Phys. Rev. Lett. 78 , 927-930 (1997).

K.A. Kouznetsov, A.G. Sun, B. Chen, A.S. Katz, S.R. Bahcall, J. Clarke, R.C. Dynes, D.A. Gajewski, S.H. Han, M.B. Maple, J. Giapintzakis, J.-T. Kim and D.M. Ginsberg, C-axis Josephson Tunneling Between and Pb: Direct Evidence for Mixed Order parameter Symmetry in a High-Tc Superconductor, Phys. Rev. Lett. 79, 3050 - 3053. (1997).

A.S. Katz, A.G. Sun, S.I. Woods,and R.C. Dynes, Planar thin film Josephson functions via nanolithography and ion damage, Appl. Phys. Lett. 72, 2032 - 2034. (1998).

A. Frydman, E.P. Price and R.C. Dynes, Conductance Fluctuations in Mesoscopic Granular Superconductors, SSC 106, 715-719 (1998)

NEW. S.I. Woods, A.S. Katz, M.C. de Andrade, J. Hermann, M.B. Maple and R.C. Dynes, Destruction of superconductivity in thin films by ion irradiation, Phys. Rev. B 58, 8800 - 8804. (1998).

A.V. Herzog, P. Xiong and R.C. Dynes, Magnetoresistance oscillation in granular Sn wires near the superconductor-insulator transition, Phys. Rev. B 58, 14199 - 14202. (1998).

A. Frydman and R.C. Dynes, Magnetoresistance of Granular Ferromagnets - Observation of a Magnetic Proximity Effect? Accepted to Solid State Communications 2/99.

P. Xiong, B.L. Zink, S.I. Applebaum, F. Hellman, R.C.Dynes, Low-temperature magnetoresistance in insulating alloys Phys. Rev. B Rapid Communications 59, pp. 3929-3933, (1999).

Sum Rules and Interlayer Conductivity of High-Tc Cuprates D. N. Basov, S. I. Woods, A. S. Katz, E. J. Singley, R. C. Dynes, M. Xy, D. Hinks, C. C. Homes and M. Strongin, Science 283, p. 49 (1999).

For more information contact dynesdesk@ucsd.edu