Looking for New Physics in Free-Standing and Supported Metal Microstructures

We have developed a method for reliably fabricating free-standing metal microstructures using modern semi-conductor microprocessing techniques. These structures present an unique opportunity to study thin film-substrate interaction and, possibly low-dimensional phonons. The method of low -field magnetoresistance and theories of weak localization and superconducting fluctuations are used to measure the inelastic scattering rate of aluminum thin films. Results show no hint of low-dimensional phonons or substrate effects. We also used the electron heating method to study electron -phonon scattering in Cr doped Cu films. The measured temperature dependence obeys an unexpected power law which may be related to 2D phonons. A similar study of extremely narrow wires failed to detect ID phonons. Measurements on superconducting aluminum thin films with spatially modulated transition temperature show an anomalous long length scale inconsistent with established theories.