Superconducting fluctuations above <i>Tc</i> in cold-deposited indium films with hydrogen: observation of transition from two- to zero-dimensional fluctuations

The fluctuation superconductivity above Tc in indium films, obtained by deposition in a hydrogen atmosphere (at pressures pH2 ranging from 2 ⋅ 10−7 to 1.2 ⋅ 10−4 torr) on a substrate with temperature ∼3 or ∼5 °K, is investigated. For a low hydrogen content, the fluctuation conductivity of the films is described well by the Aslamazov-Larkin theory for two-dimensional systems. As the hydrogen content increases, the films become granular, and the temperature dependence of the fluctuation conductivity corresponds to the presence of zero-dimensional fluctuations of the order parameter. While investigating such films, the transition from two- to zero-dimensional fluctuations in the region T &amp;gt; Tc, predicted by the theory of Deutscher, Imry, and Gunther, is observed the first time. It is shown that the magnitude of the zero-dimensional fluctuation conductivity and the temperatures of transitions from two- to zero-dimensional behavior agree well with this theory.

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