Mesoscopic Phenomena in Magnetotransport Measurements on Two-Dimensional Systems

Summary

Magnetotransport measurements on two-dimensional electronic systems demonstrate new physical phenomena when the sample size becomes smaller than certain characteristic lengthscales such as the electronic localization length in a disordered system or the equilibration length for the electrochemical potential in adjacent edge channels. The experimental results show that, in general, the measured voltages and currents cannot be directly related to bulk parameters, such as the resistivity or the conductivity tensor components, of the infinite homogeneous system. The measurements show that the finite size of the devices modifies the metal-insulator transition for energies close to the center of a Landau level, as well as the energy dissipation due to backscattéring. The experimental data can be interpreted on the basis of the edge channel picture for adiabatic transport and the theory of localized states of a two-dimensional system in strong magnetic fields.