We observe an adiabatic transport phenomena of electrons in valley-splitting quantum Hall edge channels for the first time using a high-mobility Si/SiGe two-dimensional electron system. We find that the scattering event between the valley-splitting edge channels is suppressed over a distance of ≈5 μm, which is surprisingly longer than that expected from the valley-splitting energy gap in Si.

We study the edge-channel transport at quantum Hall (QH) transition regions for a high-mobility Si / Si Ge QH conductor by measuring nonlocal resistance (R_NL). The R_NL as a function of magnetic field changes drastically after Landau-level crossings. The features of the R_NL depend on the spin configuration between the innermost edge channel and the bulk state: the R_NL appears only when the relevant edge-bulk states have opposite spin orientations. Also, an origin of the spin-dependent resistivity [Phys. Rev. Lett. 94, 176402 (2005)] at QH transition regions is discussed in terms of the spin-dependent inter-edge-bulk scattering.