Professor John Gregg

Abstract:

We present a joint experimental and theoretical study on the transport properties of nickel nanoconstrictions. The samples show highly non-linear and asymmetric I-V characteristics when the conductance is smaller than G(0) = 2e(2)/h, and huge magneto resistance ratios exceeding 99.9%. We model a single point contact in a two-band tight-binding model as a 2 x 2 nickel chain connected to two semi-infinite nickel leads. The magnetoresistance is calculated by using a non-equilibrium Green's function technique. (C) 2003 Published by Elsevier B.V.

Abstract:

A novel high gain silicon based spin transistor was presented. The spin transistors were fabricated using standard photolithography on n- and p-type silicon-on-insulator (SOI) wafers. The results showed that connected in common emitter configuration and measured at room temperature, the transistor exhibited similar characteristics to that of a conventional bipolar transistor, except the current gain is negative.