Four Terminal Resistance of a Multichannel Electron Waveguide
We have measured the four terminal magnetoresistance of a multichannel electron waveguide, i.e. a submicron wire fabricated in extremely high mobility GaAs/AlGaAs heterostructure. Only a few transverse, one dimensional subbands or channels carry the current in this submicron wire because the width is comparable to an electron wavelength. We observe that the average resistance increases when the current path bends through a junction at or beyond the voltage terminals, and attribute the increase to a change (due to the bend) in the relative transmittance of the few transverse channels which carry the current. Our observations reveal that in these devices the average resistance is predominately associated with scattering from the leads used for the measurement.
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