Correlation between Hall plateau overshoot and Landau level coincidences in Si/ Si$_{1-x}$Ge heterostructures

We observe anamolous overshoots in the Hall resistance $R_{\mathrm {xy}}$ at even quantized plateaus and compare their positions to the Landau level crossings in the longitudinal resistance $R_{\mathrm {xx}}$ in a double valley degenerate Si/ Si$_{1-x}$Ge heterostructure in a tilted magnetic field $B$. Though such $R_{\mathrm {xy}}$ overshoots have been previously observed, their underlying cause is still in dispute. The magneto-transport data is measured on a Hall bar 20 $\mu$m wide with a length to width ratio of 20, etched on a 2DEG with density $n$ = $3.4\times 10^{11}$ cm$^{-2}$ and mobility $\mu$ = 70,250 cm$^{2}$/Vs. The sample shows overshoot at 0$^{\circ}$ tilt angle. Overshoots also appear at the even filling factors $\nu$ = 6, 10, 14 {\em etc.} at an angle of 76.3$^{\circ}$ and at $\nu$ = 8, 12, 16 {\em etc.} at 79.41$^{\circ}$ while disappearing at the previous factors. The angles at which the Landau level's coincide are identified from the longitudinal resistance $R_{\mathrm {xx}}$ minima and differ from the angles of maximum overshoot. These results will be discussed in the light of the recent theory of remnant incompressible strips by Siddiki et al.[1] \newline\newline[1] A. Siddiki, J. Horas, J. Moser, W. Wegscheider, and S. Ludwig. Euro. Phys. Lett., 88(1), OCT 2009.