Giant growth of quantum oscillations in an inhomogeneous 2D electron system
Dolgopolov V.T., Shashkin A.A., Kravchenko G.V., Mukhametzhanov I.M., Wendel M., Kotthaus J.P., Molenkamp L.W., Foxon C.T.
We experimentally detect for the first time that the connection of 2D electron systems with different electrochemical potentials results in long-range (> 50 μια) electron density disturbances. When a gated region of the Corbino sample is strongly depleted, the amplitude of the magneto-resistance oscillations caused by high density ungated regions is found to increase proportionally to the sample resistance which is dominated by low density regions with small conductivity. The experiments on the samples with an artificial potential profile (antidots and etched rings) below the gate show that the observed effects are not due to contact effects. PACS 71.30.+L, 72.20.My