Abstract
The electrical transport properties in sample 1 of impurity concentration n=xx of the 70Ge: Ga system are studied in the absence of a magnetic field and at low temperature in the range 0.53 to 0.017 K. It is noted that the electrical conductivity of sample 1 exhibits a metallic behavior. We found that the exponent S is equal to 0.5 (σ=σ(T=0)+mTs). This result is in agreement with the theory of weak localization (WL) at 3D and the theory of electronelectron interactions (EEI). We also found that sample 1 is located near the metal-insulator transition (MIT) of the metallic side.
Highlights
Introduction and theoretical partDepending on their electrical properties, materials can be classified as metallic or insulating systems
On the insulating side of the metal-insulator transition (MIT), the electrical transport is dominated by variable range hopping (VRH) [7,8,9,10,11,12,13], corresponding to the strong localization regime; the electrical conductivity of doped semiconductors varies according to an exponential law with the temperature of the type:
We have plotted the variation of the function w (T) as a function of ln (T) for sample 1(n=1.861×1017cm-3 in the absence of magnetic field and in the tempera-ture interval 0.017 K -0.53 K. The slope of this plot is strictly positive which indicates that sample 1 is on the metallic side of the MIT
Summary
Introduction and theoretical partDepending on their electrical properties, materials can be classified as metallic or insulating systems. On the metallic side of the metal-insulator transition (MIT), the temperature dependence of electrical conductivity for three-dimensional metallic samples at low temperatures can be expressed as follows:
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