We report on the scaling analysis of low temperature electron transport properties of nominally uncompensated neutron-transmutation-doped 70Ge:Ga samples in the critical regime for the metal-insulator transition. Ga concentration (N) and temperature (T) dependent conductivities σ(N,T) are shown to collapse onto a single universal curve using finite temperature scaling of a form σ(N,T) ∝ Tx f(|N/Nc - 1|/Ty) with x ≈ 0.38 and y ≈ 0.32 for the very small region of N = Nc ± 0.004Nc. The conductivity critical exponent μ = x/y = 1.2 ± 0.2 found from this analysis is significantly larger than μ ≈ 0.5 found from the analysis we performed previously on the same series of samples covering the much larger region of the concentration Nc < N < 1.4Nc. Determination of the true critical region, either N = Nc ± 0.4% or N = Nc ± 40%, is necessary in the future for the reliable determination of μ in Ge:Ga.
|ジャーナル||Annalen der Physik (Leipzig)|
|出版ステータス||Published - 1999 12 1|
|イベント||Proceedings of the LOCALIZATION 1999 International Conference on 'Disorder and Interaction in Transport Phenomena' - Hamburg, Ger|
継続期間: 1999 7 29 → 1999 8 3
ASJC Scopus subject areas
- Physics and Astronomy(all)