Real-space and energy representations for the interface-roughness scattering in quantum-well structures

We show that the real space representation of the interface roughness as a fluctuating potential in the coordinate space is equivalent to the usual en ergy-fluctuation representation for intrasublevel scattering in multi-inter face quantum well structures with generally shaped confinement-potential pr ofiles. The coordinate picture is, however, more general and can be used fo r higher-order effects and multi-sublevel scattering in tunnel-coupled mult i-quantum-well structures. The result is employed to study the interface-ro ughness-limited mobility of tunnel-coupled double quantum wells at low temp eratures.