Transverse "resistance overshoot" in a Si/SiGe two-dimensional electron gas in the quantum Hall effect regime

We investigate the peculiarities of the "overshoot" phenomena in the transverse Hall resistance R_xy in Si/SiGe. Near the low magnetic-field end of the quantum Hall effect plateaus, when the filling factor v approaches an integer i, R_xy overshoots the normal plateau value h/ie². However, if magnetic field B increases further, R_xy decreases to its normal value. It is shown that in the investigated sample n-Si/ Si_0.7Ge_0.3, overshoots exist for almost all v. Existence of overshoot in R_xy observed in different materials and for different v, where splitting of the adjacent Landau bands has different character, hints at the common origin of this effect. Comparison of the experimental curves R_xy (v) for v = 3 and v = 5 with and without overshoot showed that this effect exists in the whole interval between plateaus, not only in the region where R_xy exceeds the normal plateau value.