A poor man's interpretation of the Nozières-Gallet effect

Summary An interpretation of the effect proposed theoretically by Nozières and Gallet (and experimentally observed in⁴He), according to which the growth ratev of a crystal surface just below the roughening temperatureT _R is approximately linear in the disequilibrium Δμ, is given in terms of the properties of the nucleation process in the presence of a characteristic length l. The physical meaning ofl is the distance over which information can propagate on the surface before a new layer is formed. The nucleation barrier is lowered, because the size of a critical nucleus cannot exceedl, the latter being in turn proportional tov ^−1/2. A self-consistency condition ensues. The effect takes place when the correlation length ξ, which diverges atT _R, becomes comparable tol. In honour of Prof. Fausto Fumi on the occasion of his retirement from teaching.