QUANTUM CONDUCTANCE FLUCTUATIONS IN THE LARGE-SIZE-SCALE REGIME

We report the results of experimental studies of ''universal'' conduct ance fluctuations in a variety of millimeter-sized GaAs/AlxGa1-xAs het erostructures. The ability to observe these mesoscopic fluctuations in traditionally macroscopic semiconductor devices is due to the enhance d sensitivity of our magnetic field modulation measurement technique, which allows a coherent interference effect to be observed and studied in the large-size-scale regime where both the sample length and width are much greater than the quantum scattering lengths.