MAGNETOTRANSPORT IN A CHAOTIC SCATTERING CAVITY WITH TUNABLE ELECTRON-DENSITY

We have measured the resistance versus magnetic field and Fermi energy for two stadium-shaped cavities in which chaotic scattering is expect ed. We fit the power spectra of the magnetoresistance fluctuations to semiclassical chaotic scattering theory and find a characteristic fiel d which scales with cavity dimensions as predicted by classical simula tions. Measurements of conductance versus Fermi energy indicate a sign ificant contribution from short, non-chaotic paths. We have also studi ed the energy-averaged conductance as a function of magnetic field. We observe a ballistic weak localization effect similar to that predicte d by recent calculations.