IMPURITY AND BOUNDARY ROUGHNESS SCATTERING IN GAAS-ALXGA1-XAS ELECTRON WAVE-GUIDES

A characteristic decay length of the ballistic transport is studied by measuring the transfer resistance R(T). The ballistic mean free path L(B) over which the momentum-memory is conserved is found to be less than the transport mean free path due to frequent small angle scatterings. Diffuse boundary roughness scattering strongly reduces L(B) when the channel width is decreased. The amplitude of the zero-field peak in R(T) does not obey the size scaling predicted by the classical model when the boundary roughness disturbs the momentum-memory.