Conductivity of weakly and strongly localized electrons in a n-type Si/SiGe heterostructure

Shlimak, I., Ginodman, V., Levin, M., Potemski, M., Maude, D.K., Gerber, A., Milner, A. and Paul, D.J. (2004) Conductivity of weakly and strongly localized electrons in a n-type Si/SiGe heterostructure. Physica Status Solidi C, 1(1), pp. 67-70. (doi:10.1002/pssc.200303643)

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Abstract

We have investigated the temperature dependence of the longitudinal conductivity σxx and Hall resistance Rxy of n‐type Si/SiGe heterostructures in the quantum Hall effect regime in magnetic fields up to 23 T. It is shown that for odd integer filling factors i = 3,5,7,9, when the Fermi level EF is situated between the valley‐split Landau levels, Δσxx(T) ∝ lnT, which is typical for weakly localized electrons. In the case of even i, when EF lies between spin‐split or cyclotron‐split levels, σxx(T) is characteristic of strong localization: activation of localized electrons from EF to the nearest mobility edge: σxx ∝ exp[−Δi/T] for i = 6, 10, 12 or variable‐range‐hopping via localized states in the vicinity of EF: σxx ∝ exp[−(T0i/T)]1/2 for i = 4, 8. For i = 3, 6, 8, 10, 12, the Hall resistance Rxy first overshoots the quantized plateau values h/ie2 and then returns. The explanatory model involves the temporary parallel contribution of the delocalized and weakly localized electrons with different mobilities in the measurement of the Hall voltage Vxy.

Item Type:Articles
Additional Information:Special Issue: 10th Conference on Hopping and Related Phenomena (HRP10). V. G. and M. L. thank the "KAMEA" Programme for financial support.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Paul, Professor Douglas
Authors: Shlimak, I., Ginodman, V., Levin, M., Potemski, M., Maude, D.K., Gerber, A., Milner, A., and Paul, D.J.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Research Group:Semiconductor Devices
Journal Name:Physica Status Solidi C
Publisher:Wiley
ISSN:1862-6351
ISSN (Online):1610-1642
Published Online:26 November 2003

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