LOW TEMPERATURE CONDUCTANCE OF THIN METAL WIRES AND FILMS
Abstract
The topic of this thesis is the study of electrical conduction in one and two dimensional systems; specifically the effects predicted by localization and electron-electron interaction theory. We have measured the resistance of wires with very small cross-sectional areas at low temperatures. We find at low temperatures that the resistance varies as T('- 1/2) and that the magnitude of the resistance rise is inversely proportional to the area, as found previously by others. From an analysis of the temperature dependence of the resistance, we find a characteristic length of 0.18 (mu)m at 1K for Pt and AuPd wires, which is the same length found by others. We have also measured the resistance of thin Pt and AuPd films and find that the resistance increases as the temperature decreases. This increase varies as the logarithm of the temperature, and the magnitude of the increase is proportional to the sheet resistance for films with sheet resistances less than about 2 K(OMEGA). A method for fabricating short wires and films was developed to determine the characteristic length by measuring the length dependence of the resistance rise. According to the theories, the behavior of the wires and films should change when the length of the wire or film is comparable to the characteristic length. For the short wires, we found this to be so, and our results are in semi-quantitative agreement with the theory. In short films, we also see an effect as the length of the film is decreased, but the results appear to be inconsistent with the theory, at least in its present form.
Degree
Ph.D.
Subject Area
Condensation
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