Crossover from strong to weak localization in the split-off impurity band in two-dimensional p -GaAs/AlGaAs structures
✍ Scribed by N. V. Agrinskaya; V. I. Kozub; D. V. Poloskin; A. V. Chernyaev; D. V. Shamshur
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 219 KB
- Volume
- 3
- Category
- Article
- ISSN
- 1862-6351
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✦ Synopsis
Abstract
A crossover from strongly localized behavior to weak localization (SL–WL) was observed in two‐dimensional modulation‐doped GaAs/Al~0.3~Ga~0.7~As structures as the impurity concentration increased. The low‐temperature dependence of the conductivity changed its character (from exponential to logarithmic) and the magnetoresistance changed its sign (from linear negative to root positive). For 2D structures, it is shown that this transition takes place in the impurity band separated from the valence band by the mobility gap whereas the effective mass in the impurity band is larger than in the valence band. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)