Giant back-scattering resonances in edge-state transport through quantum dots

We consider the origin of striking resonances, observed in the low-temperature magneto-resistance of submicron-sized quantum dots. The magnetic-field positions of the resonances are correlated to the depopulation of Landau levels in the dots, while their amplitude can correspond to a near-complete reflection of the applied current. In order to determine the origin of these features, we formulate a model for edge-state scattering in quantum dots which properly accounts for the magnetic-field-dependent evolution of their self-consistent potential profile. The resonances are thus ascribed to a sudden increase in back scattering, mediated by edge states trapped inside the dot. A similar treatment which ignores the high-field evolution of the dot profile is unable to reproduce the resonances, which we therefore conclude provide an important demonstration of the role of self-consistent effects in mesoscopic systems.