Crossover phenomenon for two-dimensional hopping conductivity and density-of-states near the Fermi level

S. I. Khondaker; I. S. Shlimak; J. T. Nicholls; M. Pepper; D. A. Ritchie

doi:10.1016/s0038-1098(99)00027-7

Crossover phenomenon for two-dimensional hopping conductivity and density-of-states near the Fermi level

S. I. Khondaker, I. S. Shlimak, J. T. Nicholls, M. Pepper, D. A. Ritchie

Department of Physics

University of Cambridge

Research output: Contribution to journal › Article › peer-review

26 Scopus citations

Abstract

The variable range hopping (VRH) resistivity in a gated δ-doped GaAs/AlGaAs heterostructure was measured at temperatures down to 280 mK. At low temperatures, the logarithm of the resistivity follows T^-1/2 behaviour, which corresponds to the existence of a soft (linear) Coulomb gap in the density of states (DOS) at the Fermi level (FL). As the temperature is increased, there is a crossover to T^-1/3 behaviour, corresponding to a constant DOS outside the Coulomb gap. A quantitative analysis of the resistivity data allows us to determine the width of the Coulomb gap and the DOS around the FL.

Original language	English
Pages (from-to)	751-756
Number of pages	6
Journal	Solid State Communications
Volume	109
Issue number	12
DOIs	https://doi.org/10.1016/s0038-1098(99)00027-7
State	Published - 9 Mar 1999

Bibliographical note

Funding Information:
This work was supported by the Engineering and Physical Science Research Council (UK). The authors thank A. Khaetskii, M. Kaveh and E. Kogan for fruitful discussions. SIK acknowledges support from the Commonwealth Scholarship Commission in the UK.

Funding

This work was supported by the Engineering and Physical Science Research Council (UK). The authors thank A. Khaetskii, M. Kaveh and E. Kogan for fruitful discussions. SIK acknowledges support from the Commonwealth Scholarship Commission in the UK.

Funders	Funder number
Engineering and Physical Sciences Research Council
Commonwealth Scholarship Commission

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10.1016/s0038-1098(99)00027-7

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abstract = "The variable range hopping (VRH) resistivity in a gated δ-doped GaAs/AlGaAs heterostructure was measured at temperatures down to 280 mK. At low temperatures, the logarithm of the resistivity follows T-1/2 behaviour, which corresponds to the existence of a soft (linear) Coulomb gap in the density of states (DOS) at the Fermi level (FL). As the temperature is increased, there is a crossover to T-1/3 behaviour, corresponding to a constant DOS outside the Coulomb gap. A quantitative analysis of the resistivity data allows us to determine the width of the Coulomb gap and the DOS around the FL.",

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AU - Pepper, M.

AU - Ritchie, D. A.

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N2 - The variable range hopping (VRH) resistivity in a gated δ-doped GaAs/AlGaAs heterostructure was measured at temperatures down to 280 mK. At low temperatures, the logarithm of the resistivity follows T-1/2 behaviour, which corresponds to the existence of a soft (linear) Coulomb gap in the density of states (DOS) at the Fermi level (FL). As the temperature is increased, there is a crossover to T-1/3 behaviour, corresponding to a constant DOS outside the Coulomb gap. A quantitative analysis of the resistivity data allows us to determine the width of the Coulomb gap and the DOS around the FL.

AB - The variable range hopping (VRH) resistivity in a gated δ-doped GaAs/AlGaAs heterostructure was measured at temperatures down to 280 mK. At low temperatures, the logarithm of the resistivity follows T-1/2 behaviour, which corresponds to the existence of a soft (linear) Coulomb gap in the density of states (DOS) at the Fermi level (FL). As the temperature is increased, there is a crossover to T-1/3 behaviour, corresponding to a constant DOS outside the Coulomb gap. A quantitative analysis of the resistivity data allows us to determine the width of the Coulomb gap and the DOS around the FL.

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Crossover phenomenon for two-dimensional hopping conductivity and density-of-states near the Fermi level

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