Diffusion Thermopower of a Two-Dimensional Hole Gas in SiGe in a Quantum Hall Insulating State

C. Possanzini, R. Fletcher, P. T. Coleridge, Y. Feng, R. L. Williams, and J. C. Maan

Phys. Rev. Lett. 90, 176601 – Published 28 April 2003

Abstract

Both the temperature dependence of resistivity and thermopower of a two-dimensional hole gas in SiGe show a reentrant metal-insulator transition at filling factor $ν = 1.5$ , but with strikingly different behavior of the two coefficients. As the temperature is decreased in the insulating state, the resistivity diverges exponentially while the thermopower decreases rapidly, suggesting that the insulating state is due to the presence of a mobility edge rather than a gap at the Fermi energy.

Received 1 December 2002

DOI:https://doi.org/10.1103/PhysRevLett.90.176601

Authors & Affiliations

C. Possanzini¹, R. Fletcher², P. T. Coleridge³, Y. Feng³, R. L. Williams³, and J. C. Maan^1,*

¹Research Institute for Materials, High Field Magnet Laboratory, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
²Physics Department, Queen’s University, Kingston, Ontario, Canada K7L 3N6
³Institute for Microstructural Sciences, National Research Council, Ottawa, Ontario, Canada K1A 0R6

^*Electronic address: maan@sci.kun.nl

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Vol. 90, Iss. 17 — 2 May 2003

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