Oral: Shot Noise Suppression in Au Nanowires

Shot noise, the time-dependent fluctuation of the electrical current in electronic circuits, arises from the discrete nature of charge carriers [1]. The measurements of shot noise have unveiled the microscopic charge dynamics underlying various quantum transport phenomena [2]. This project investigates the suppression of shot noise in gold nanowires that occurs with increasing temperature, as electron-phonon scattering rates climb, in line with previous observations. We fabricate gold nanowires, ranging from sub-micron lengths to several microns in length, each with two thick contact pads, on SiO₂/Si substrates, allowing precise shot noise measurements across a broad temperature range. Our detailed mapping reveals that at low temperatures in short wires, the Fano factor approaches the expected value ~1/3, but as the temperature rises, inelastic electron-phonon scattering suppresses shot noise. Our measurements provide supplemental support for the ongoing debate on the role of electron-phonon scattering in suppressing shot noise at the relatively high temperature.