Smectic liquid crystals in random environments

Article

关键词: NEMATIC PHASE-TRANSITION;    COMPRESSIONAL ELASTIC-CONSTANT;    VORTEX-GLASS TRANSITION;    SELF-CONSISTENT THEORY;    CHARGE-DENSITY WAVES;    X-RAY-SCATTERING;    CRITICAL-BEHAVIOR;    II SUPERCONDUCTORS;    SILICA AEROGELS;    HEPTYLOXYBENZYLIDENE BUTYLANILINE;   

DOI  :  10.1103/PhysRevB.60.206

来源: SCIE

【 摘 要 】

We study smectic liquid crystals in random environments, e.g., aerogel. A low-temperature analysis reveals that even arbitrarily weak quenched disorder (i.e., arbitrarily low aerogel density) destroys translational (smectic) order, in agreement with recent experimental results. A harmonic approximation to the elastic energy suggests that there may be no ''smectic Bragg glass phase in this system: even at zero temperature, it is riddled with dislocation loops induced by the quenched disorder. This result would imply the destruction of orientational (nematic) order as well, and that the thermodynamically sharp nematic-smectic transition is destroyed by disorder. We show, however, that the anharmonic elastic terms neglected in the above approximate treatment are important (i.e., are relevant in the renormalization group sense), and may, indeed, stabilize the smectic Bragg glass and the sharp phase transition into it. However, they do not alter our conclusion that translational (smectic) order is always destroyed. In contrast, we expect that weak annealed disorder should have no qualitative effects on the smectic order. [S0163-1829(99)09121-3].

【 授权许可】

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