Extraordinary magnetoresistance effect in a microstructured metal-semiconductor hybrid structure

We have fabricated hybrid structures consisting of a metallic thin film and of a microstructured two-dimensional electron system in an InAs heterostructure. The devices are found to exhibit a huge magnetoresistance (MR) effect in magnetic fields less than or equal to1 T. At low temperature, a value of DeltaR/R=[R(B=1 T)-R(B=0)]/R(B=0) as high as 115 000% is measured. The value of DeltaR/R has been studied as a function of the electron mobility, the electron density and the lateral width of the semiconductor. We find that the MR effect can be tailored by these different parameters and technological relevant devices can be realized. (C) 2002 American Institute of Physics.