METAL-INSULATOR-TRANSITION IN AMORPHOUS GA-AR MIXTURES - CRITICAL EXPONENTS OF ELECTRICAL TRANSPORT PARAMETERS AND BEHAVIOR OF SUPERCONDUCTIVITY

The experimentally determined critical exponents and g of electrical dc conductivity and Hall coefficient RH approaching the metal-insulator transition (MIT) from the metallic side in amorphous GaxAr1-x mixtures are =0.50.1 and g=0.030.05, respectively. These exponents are the same as those found in Si:P and Si:As. We thus conclude that the MIT in these systems belong to the same universality class. Furthermore, we find that the disappearance of superconductivity in these mixtures coincides with the MIT. © 1990 The American Physical Society.