RESISTANCE AND RESISTIVITY OF 2-DIMENSIONAL ELECTRON-GAS AT HIGH MAGNETIC-FIELDS

Resistance (or conductance) is measured both in Hall-bar devices and in "closed" devices in which a 2D EG is (almost) completely bounded by ohmic contacts. We provide quantitative account for anomalous Shubnikov de-Haas oscillations and Hall step structures in Hall bar devices, by using the results in the closed devices. Nonlocal resistance is also explained qualitatively. Our analysis uses no adjustable parameter. It treats the edge and bulk conductions independently, similarly to a recent model, but considers a partial reflection that unavoidably occurs between bulk states and ideal contacts.