Quench-condensed indium-hydrogen films. II. Changes in electric and superconducting characteristics near the metal-insulator transition |
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Authors: | B I Belevtsev Yu F Komnik V I Odnokozov A V Fomin |
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Affiliation: | (1) Institute for Low Temperature Physics and Engineering, Kharkov, USSR |
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Abstract: | Electrical and superconducting properties of indium films condensed in a H2 atmosphere (pressurep
H
2=6×10−6 to 1.4×10−4 Torr) onto a substrate cooled with liquid helium are investigated. As hydrogen content is increased, a continuous increase
in residual resistivity ρ* is observed, permitting systematic study of the resistance vs. temperature dependenceR(T) and the superconducting transition temperatureT
c on approaching the metal-insulator transition (MIT). With regard to ρ*, four regimes of conductivity can be observed: (1)
conductivity with a positive temperature resistance coefficient (TRC), (2) conductivity with a small, constant, negative TRC,
(3) conductivity under weak localization with ΔR (T) ∼ln T or
type corrections, (4) hopping conductivity.T
c rises continuously with ρ* and reaches its peak (∼5.2K) in the second regime. A further increase of ρ* leads to a decrease
ofT
c and complete suppression of superconductivity. The experimental dependenceR(T) is compared with theory. TheT
c variation on approaching the MIT and the relation between Mooij's rule and the superconducting properties are discussed. |
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Keywords: | |
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