Nematic--to--Smectic-A Transition in Aerogel

Abstract

We study a model for the Nematic--Smectic-A (NA) transition in aerogel, and find that even arbitrarily weak quenched disorder (i.e., low aerogel density) destroys translational (smectic) order. Ignoring elastic anharmonicities, but keeping anharmonic couplings to disorder, leads to the prediction that there is no ``Bragg glass'' phase in this system: it is riddled with dislocation loops induced by the quenched disorder. Orientational (nematic) order is destroyed as well, as is the thermodynamically sharp NA transition, in agreement with recent experimental results.

version to appear in Phys. Rev. Lett., minor changes and references added

References in corpus (1)

• Dirt Softens Soap: Anomalous Elasticity of Disordered Smectics

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