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Variable-Range Hopping in the Array of Magnetic Quantum Dots

Published online by Cambridge University Press:  17 March 2011

M. Foygel ,
R. D. Morris  and
A. G. Petukhov
M. Foygel
Affiliation:
Physics Department, South Dakota School of Mines and Technology, Rapid City, SD 57701-3995
R. D. Morris
Affiliation:
USRA/RIACS, NASA Ames Research Center, Moffet Field, CA 94035-1000
A. G. Petukhov
Affiliation:
USRA/RIACS, NASA Ames Research Center, Moffet Field, CA 94035-1000
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Abstract

We analyzed the spin-dependent conductivity in the system of paramagnetic quantum dots embedded in semi-insulating matrix, which is due to bound magnetic polaron (BMP) inter-dot hopping. If such a system is characterized by wide distributions of the “bare” electron energies and BMP shifts, variable-range and variable-polaron-barrier hopping can be observed at low temperaturesT. It results in the giant magnetoresistance,ρ(H, T ) governed by a non-activation law, lnρ /α [T0(H)/T ]p, whereT0(H) drops with magnetic field,H. Depending on the conditions, parameters of the material, and the dimensionality of the system, the exponent 0.25 < p < 0.75. This type ofT -dependence has been observed in GaMnAs and MnGe magnetic semiconductors.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 690: Symposium F – Spintronics , 2001 , F10.7
Copyright
Copyright © Materials Research Society 2002

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References

REFERENCES

[1] Schmidt, D., Petukhov, A.G., Foygel, M., Ibbetson, J. P, and Allen, S. J., Phys. Rev. Lett 82, 823 (1999).Google Scholar
[2] Dietl, T., Antozsewski, J. and Swierkowski, L., Physica 117B & 118B, 491 (1983).Google Scholar
[3] Ioselevich, A. S., JETP Lett. 43, 188 (1986); Phys. Rev. Lett. 71, 1067 (1993).Google Scholar
[4] Petukhov, A. G. and Foygel, M., Phys. Rev. B62, 520 (2000).Google Scholar
[5] Esch, A. Van, Bockstal, L. Van, Boeck, J. De, Verbanck, G., Steenbergen, A. S. van, Wellmann, P. J., Grietens, B., Bogaerts, R., Herlach, F., Borghs, G., Phys. Rev. B 56, 13103 (1997); T. C. Kreutz, G. Zanelatto, R. Kawakami, E. Johnston-Halperin, E. J. Gwinn, A. C. Gossard, D. D. Awschalom, AVS 48th International Symposium, San Francisco, CA, 2001, p.98; P. A. Crowell, private communication.Google Scholar
[6] Park, Y. D., Wilson, A., Hanbicki, A. T., Mattson, J. E., Ambrose, T., Spanos, G., Jonker, B. T., Appl. Phys. Lett. 78, 2739 (2001).Google Scholar
[7] Shklovskii, B. I. and Efros, A. L., Electronic Properties of Doped Semiconductors, Springer Series in Solid State Sciences, vol. 45 (Springer-Verlag, Berlin, 1984).Google Scholar
[8] Dietl, T. and Spalek, J., Phys. Rev. B 28, 1548 (1983).Google Scholar
[9] Helman, J. S. and Abeles, B., Phys. Rev. Lett. 37, 1429 (1976).Google Scholar
[10] Ioselevich, A. S.. Phys. Rev. Lett. 74, 1411 (1995).Google Scholar