Effect of correlated disorder on the temperature of unconventional Cooper pairing (3He in aerogel)
Abstract
Using liquid 3He in aerogel as an example, it is shown that correlations in positions of impurities affect the temperature Tc of transition of Fermi liquid in an unconventional superfluid or superconductive state. The effect is significant if the correlation length for impurities is greater than the coherence length in the superfluid or superconductive state 0. For 3He in aerogel the suppression of Tc is expressed in terms of the structure factor of aerogel. With the account of the fractal structure of aerogel a simple expression is obtained for the decrease of Tc from its clean value. This expression is in a satisfactory agreement with experimental data.
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