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

TL;DR

This study investigates the overshoot phenomenon in the transverse Hall resistance of Si/SiGe in the quantum Hall regime, revealing its widespread occurrence across various filling factors and suggesting a common underlying mechanism.

Contribution

It demonstrates that the resistance overshoot occurs across nearly all filling factors in Si/SiGe and other materials, indicating a universal origin of this effect in the quantum Hall regime.

Findings

Overshoot exists for almost all filling factors in Si/SiGe.

The overshoot phenomenon is observed across different materials and Landau level splittings.

Overshoot occurs throughout the interval between quantum Hall plateaus, not only at the peaks.

Abstract

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 \nu approaches an integer i, R_{xy} overshoots the normal plateau value h/ie^2. 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_{0.7}Ge_{0.3}, overshoots exist for almost all \nu. Existence of overshoot in R_{xy} observed in different materials and for different \nu, 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}(\nu) for \nu = 3 and \nu = 5 with and without overshoot showed that this effect exist in the whole interval between plateaus, not only in the region where R_{xy} exceeds the normal plateau value.