CONDUCTANCE FLUCTUATIONS IN PBSE - MANIFESTATION OF BALLISTIC TRANSPORT IN MACROSCALE

Precise magnetoresistance measurements on microstructures of photolith ographically patterned PbSe epilayers have been performed in the magne tic field range up to 17 T. Unusually large, reproducible magnetocondu ctance fluctuations have been observed. The fluctuation amplitude decr eases exponentially with the magnetic field. A correlation magnetic fi eld of the fluctuations corresponds to the Aharonov-Bohm effect which involves electron trajectories much smaller than the electron mean fre e path. This points strongly to the ballistic, not diffusive, origin o f the observed phenomenon.