Emilio Mendez

Department of Physics and Astronomy, SUNY Stony Brook, New York

 

Do you know which of Einstein's three major contributions in 1905 is the most cited? Not relativity or the photoelectric effect, but his explanation of Brownian motion. With this work, Einstein not only helped settle the question about the reality of atoms but also established statistical mechanics as the tool to understand many other fluctuations in Nature, from physics to biology to nanotechnology.

In electronics, the fluctuations in the current along a conductor are known as noise and are a consequence of the electrons’ thermal motion, defect-induced electron traps, and the quantization of charge. For a physicist, of these contributions to noise the third one is the most interesting because, being intrinsic, it gives information about the microscopic mechanisms of electric conduction and it sets the fundamental limits of device performance, especially in nanoelectronic devices, in which the shot noise can be most important.

In this lecture, after highlighting some landmarks on the study of electric fluctuations that include the confirmation of fractional charge in the fractional quantum Hall effect, I will focus on the noise properties of some nanoscale systems. Specifically, I will present experiments in short metal wires, semiconductor superlattices and resonant-tunneling devices that illustrate how shot noise complements conductance in elucidating the electron transport mechanisms.