Abstract
A method has been developed for determining the effective concentration of shallow impurities N* reponsible for the low-temperature conductivity in the vicinity of the metal-insulator transition for inhomogeneous samples of n-Ge:As. The method is based on the measurement of two ratios of sample resistance γ-R(4.2 K)/R(300 K), β=R(2.0 K)/R(4.2 K) and the conductivity σ(4.2 K). The next step consists of plotting and σ(4.2) vs β. Assuming that β is the most reliable parameter, one can calculate, after an averaging procedare, the corrected values of γ*, π*(4.2) and the resistivity at room temperature ρ*(300)=[γ*π*(4.2)]-1. Finally, using the known dependence ρ(300)=f(N) for homogeneous samples, one can obtain the values of N*. The dependences of N* on β and on γ are plotted. The scaling behavior of the conductivity of the Ge:As samples with corrected values of π*(4.2) and N* has been observed down to T=100 mK.
Original language | English |
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Pages (from-to) | 115-118 |
Number of pages | 4 |
Journal | Applied Physics A: Materials Science and Processing |
Volume | 61 |
Issue number | 2 |
DOIs | |
State | Published - Aug 1995 |
Keywords
- 72.20
- 81.40