Europhys. Lett.
Volume 69, Number 6, March 2005
Page(s) 997 - 1002
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 23 February 2005
Europhys. Lett., 69 (6), pp. 997-1002 (2005)
DOI: 10.1209/epl/i2004-10454-4

Transverse "resistance overshoot" in a $\chem{Si/SiGe}$ two-dimensional electron gas in the quantum Hall effect regime

I. Shlimak1, V. Ginodman1, A. B. Gerber2, A. Milner2, K.-J. Friedland3 and D. J. Paul4

1  Minerva Center and Jack and Pearl Resnick Institute of Advanced Technology Department of Physics, Bar-Ilan University - 52900 Ramat-Gan, Israel
2  School of Physics & Astronomy, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University - 69978 Tel Aviv, Israel
3  Paul-Drude-Institut für Festkörperelektronik - Hausvogteiplatz 5-7 10117, Berlin, Germany
4  Cavendish Laboratory, University of Cambridge Madingley Road, Cambridge CB3 0HE, UK

received 15 October 2004; accepted in final form 31 January 2005
published online 23 February 2005

We investigate the peculiarities of the "overshoot" phenomena in the transverse Hall resistance Rxy in $\chem{Si/SiGe}$. Near the low magnetic-field end of the quantum Hall effect plateaus, when the filling factor $\nu$ approaches an integer i, Rxy overshoots the normal plateau value h/ie2. However, if magnetic field B increases further, Rxy decreases to its normal value. It is shown that in the investigated sample n- $\chem{Si/Si_{0.7}Ge_{0.3}}$, overshoots exist for almost all $\nu$. Existence of overshoot in Rxy 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 exists in the whole interval between plateaus, not only in the region where Rxy exceeds the normal plateau value.

73.43.-f - Quantum Hall effects.
72.20.Ee - Mobility edges; hopping transport.

© EDP Sciences 2005